What did Kumoko do to raise Taboo?

Question

What exactly were all the things Kumoko did to raise her Taboo skill? I know she ate a sibling, but the other ones kind of went by fast. I'd like a list of them.

Answer 1

Taboo is an interesting skill, but some of the ways Kumoko levels it up are very uninteresting, as it levels up several times when she evolves. I will try to list how she got each level, but it isn't 100% clear in one case.

Level 1: Ate a sibling

She first gains the skill by eating one of her siblings. It comes with the Kin Eater title she acquires as a result. From the first light novel, chapter 2: A Rent-Free Home:

So I press on and finish eating my sibling's carcass. This is enough to fill my stomach, so I don't have to worry about starvation for a while.
Whew. Thanks for the meal, I guess.
<Condition satisfied. Acquired title [Kin Eater].>
<Acquired skills [Taboo LV 1][Heretic Magic LV 1] as a result of title [Kin Eater].>

Uh, what?

Level 2: Evolved into a small taratect.

This happens on page 113 of the first light novel. Seemingly all Kumoko does is evolve into a small taratect. It doesn't seem like a particularly controversial choice. Skills often level up from proficiency bonuses while leveling up, so that could be what's going on here. Kumoko gets a skill proficiency evolutionary bonus while leveling up. If this is really the case, it doesn't seem particularly fair to automatically level up a negative skill like taboo, described as "Must never be raised." I'll note that on page 152, in chapter 9: Spider vs Bee, Kumoko says this about skills:

And with this latest level-up, three of my skills powered up too.

I don't really know what any of them did, but if they leveled up, I must be earning proficiency for them somehow, so it's possible that I'm benefiting from them without even realizing it.

She's not talking about Taboo here, but if this is really true in general, Kumoko might be doing something to earn Taboo proficiency, and it just only happens to level up when she evolves. It's noteworthy though that she never gets a Taboo level up just from leveling up, unlike a lot of her other skills. There's really no way to know at this point, and I can really only go off of what the light novel says. Though perhaps relevant then, is when she gets the Merciless title on page 242, which comes with some more Heretic Magic and Heresy Resistance. She gets this title after slaughtering a large number of the monkey horde that comes after her. Her attitude at the moment is probably what gives her the title:

I sense a hint of fear in their cries, too, but what do I care about that?
They're the ones who picked a fight with me, so they should've been prepared to die themselves.
You're not gonna catch me losing any sleep over killing something that tried to kill me first.
So I ignore their struggles and finish them off.

Heresy Magic is notably ominous sounding, and it also came with Taboo, so her proficiency for Taboo may have gone up here for one reason or another.

Level 3 and Level 4: Acquiring the skill Pride

Moving on to volume 2, on page 26 her Taboo level jumps up to level 4 after she acquires the skill pride for the bargain price of 100 skill points. Since she'd decided to live her life with pride, she may have gained an affinity for the skill which might explain the cost. And if pride is connected with Taboo, being prideful could again be giving her proficiency in Taboo behind the scenes (later on, with a maxed-out Appraise, Kumoko is finally able to see her current proficiency and how close it is to leveling up, but at this point, she can only see the current level). Taboo goes up immediately after she gets the skill Pride, even before she gets the title Ruler of Pride and the abyss magic that comes with it, so we can be reasonably sure that it's acquiring this skill that increased Taboo by two levels.

Level 5: Evolving into Zoa Ele

This happens on page 131 of book 2. Again, another evolution boost. It's noteworthy that Taboo doesn't go up for every evolution, as it didn't level up for her evolution to Poison Taratect. Zoe Ele is notable for being described as "A small-spider type monster that is feared as an ill omen", so it does seem more taboo than her past evolutions at least. For further comments, see Level 2.

Level 6 and Level 7: Acquiring the skill Perseverance

On page 139 of book 2, Kumoko acquires the skill Perseverance for 500 skill points. It lets her survive lethal attacks by sacrificing MP, and it has a lot of the same terminology in its description as Pride, and comes with a Ruler of Perseverance title, just like the Pride one.

Level 8: Acquiring the skill Wisdom from Administrator D

In volume 2, page 175 in chapter 7: The Administrator's Shadow, Kumoko is complaining to herself that Appraise didn't evolve into any new skill, but it seems someone is listening:

< Upper Administrator D has accepted the request>
<Now constructing skill [Wisdom].>
< Construction Complete.>
<Condition satisfied. Acquired skill [Wisdom].>
<Skill Appraisal LV 10> has been integrated into [Wisdom].>
<Skill [Detection LV 10] has been integrated into [Wisdom].>
<Proficiency has reached the required level. Skill [Taboo LV 7 has become [Taboo LV 8].>
<Condition satisfied. Acquired title [Ruler of Wisdom].>
<Acquired skills [Height of Evil] [Celestial Power] as a result of title [Ruler of Wisdom].

It's not entirely clear why Taboo levels up. It could have something to do with the contact with Administrator D, but considering Wisdom and it's title seem similar to Pride and Perseverance, and considering Taboo levels up immediately after acquiring Wisdom, it probably is the skill that does it.

Level 9: Eating a Fire Dragon?

How Kumoko levels up Taboo to 9 is unclear in the light novels. It comes after having directly spoken with Administrator D following her defeat of the Fire Dragon in book 3. It does seem the death of a dragon is concerning, even to an administrator, as this is why Güliedistodiez tracks Kumoko down afterward (though is interrupted by Administrator D), as evidenced by this mysterious passage at the end of chapter 4: Dragon Slayer:

"A dragon's been destroyed? In the Great Elroe Labyrinth... Was this his doing? No, I don't think so. We have an unspoken truce going on. I don't think he would make a move like that. But what happened then? Activate Administrator's authority... What in the world? A ruler? Of three, no less? What does this mean? I've never heard of this skill 'Wisdom'. Does that mean this is the work of D? But why? What is this skill? ...I guess I'll have to investigate.

This is the passage where Kumoko levels up Taboo at the beginning of chapter 6: Middle Stratum Cleared:

I eat.
And eat.
And eat.
It's bitter.
So bitter.
Bitter, just a little sweet, and sad.
<Proficiency has reached the required level. Skill [Taboo LV 8] has become [Taboo LV 9].>

At this point, it isn't obvious whether or not what Kumoko's eating is dragon or not. It seems probable since she does check the skills she got from defeating it, so not much time could have passed, and also because she was descaling it when the Administrator arrived. Another possibility is thinking too much about the Administrators. This is obviously what's on her mind as she eats, and she's annoyed at them, thinking bad thoughts about deities including how she probably couldn't defeat Administrator D if she fought her, which seems like Taboo thoughts, so it's possible that's what raised Taboo, though it isn't really substantiated. Here's the passage:

Otherwise, that would mean this whole world exists as a sideshow for D's amusement

I don't like the sound of that

...

Aside from that, I don't have enough information to do anything but speculate.

So I have to conclude there's no point in racking my brains about "D," "administrators," and all that jazz any further.

Honestly, it's not like I can do anything about it anyway.

If beings that can control the skill system want to mess with me, I doubt I could put up much resistance.

Trying to go up against an administrator would be like trying to stop a meteor from destroying the earth.

That's not the kinda thing I can win against.

Not just D, either. That dark guy who showed up in front of me earlier seemed way more powerful than me, too.

...

Never mind a contest of strength. I wouldn't even be able to qualify for the game.

Later in the chapter, we do glean something that raised Taboo partway up to the level up though:

I also maxed out Heretic Magic.
But you'll never guess what god-awful skill derived from that.
Taboo.
Luckily, it didn't level up, but I thought my heart was going to stop for a second.
Actually, even though it didn't level up at that moment, it's hit level 9 at some point without my noticing.
One more level and it'll be maxed out.
This could be really bad.

Level 10: Evolving into Ede Saine

Like the Zoa Elle, this evolution does have a foreboding description: "a small spider-type monster feared as an omen of death.", but this may or may not explain Taboo going up. See Level 2 for further comments.

More Taboo

That's it for Kumoko's leveling up for Taboo, but here are a few more examples for ways to level up Taboo from some other characters.

Fei gains Taboo just for biting the earth wyrm that shows up to attack the students. Apparently, this is sufficient for gaining the Kin Eater title. It's probably that she ingested at least a small amount of the wyrm, but it is still a bit surprising. (Note, she didn't kill the earth wyrm, which was probably her parent; Shun did.)

Then I notice her new title.
[Kin Eater]
As its name suggests, it's a terrible title conferred on those who have eaten the flesh of a blood relative.
"It...can't be..."
"I don't see any other explanation, do you?"
Fei must have bitten right through the wyrm's neck.
If so, her grant of this title would make sense.
In fact, that's the only way it could have happened.

From even further down the line, Shun's Mercy skill levels up Taboo rapidly.

This skill allows Shun to resurrect the dead, and he uses it to save Katia after she blows herself up to free herself from Hugo's brainwashing, and after their execution Shun uses it to save Katia's parents and one of his elder brothers, even going so far as to put their heads back on after they were chopped off (he had to do this himself, as the skill wouldn't work if the heads were detached).

From page 166-167 of the third light novel, Shun's Taboo level jumps from level 5 to level 9 :

Mercy.
A forbidden skill that resurrects the dead.
This is the skill Katia questioned me about, saying it was no ordinary magic. A skill that brings about miracles.
That time, when Katia fired magic at herself to get rid of the brainwashing, she really was mortally wounded.
Her HP dropped to 0, and she died.
However, I used this skill right away and brought Katia back from the dead.
Once I revive Leston, I do the same for Klevea and Katia's parents.
In the process, my MP all but runs out, and my Taboo skill level goes up to 9.
Mercy is probably the only skill in existence that can revive the dead, but it has serious conditions and disadvantages too.
Firstly, it consumes a large amount of MP.
The only reason I could revive four people was because my skills greatly increased when I became the hero.
Also, if the body is too damaged, it can't be revived.
This time, I was able to reattach the severed heads to their bodies, but if I tried it with only one or the other, it probably wouldn't have worked.
Finally, it's only effective for a short period of time after a person's death.
I haven't experimented with it, of course, so I don't know exactly how long, but my sense is that it's probably only a few minutes.