Episode 4 of All Out!! closes with the following end card, on screen for 10 seconds beginning @23:50
It appears to be a signed image, and my assumption is that neither the mangaka nor the animation staff drew it. This looks like fan art to me, something they might have found at Deviant Art and got permission to use.
I know the high school rugby players of the series tend to be very muscular in the body-building sense. This drawing, though, seems to overdo it. Their pecs are more reminiscent of a women's breasts than male anatomy. In the other sports anime I have seen, Haikyuu!, Free!, and Yuri on Ice, the athletes are well-developed, but lither. I can't tell if this image was drawn by a muscle fetishist or just someone who had not yet mastered anatomy.
Checking episodes 1-3, I see they all also have 10-second end cards, drawn in a different style than the anime. The episode 1 end card is another grey-scale image signed by the same person. The pecs are not as exaggerated, though. (I assume that Japanese text is a signature -- for all I know, it says, "Hi, mom!" )
Does anyone know if these end cards are amateur works, draft images done by the animation staff, or by the mangaka? I like them; they give extra personality to the series. I'm curious because I don't remember seeing this sort of thing before.
