WARNING: The following contains spoilers for So I’m a Spider, So What? Episode 5, “Does Catfish, Taste Good?,” streaming now on Crunchyroll.
So I'm a Spider's Episode 5 dives into the advantages of developing one’s skills, and there's one in particular that has the followers of ‘God’ adopting a peculiar mindset. Both Fei and Wakaba have acquired the 'Taboo' skill from killing their own kin, which is obviously not an objectively good thing, but why is it so highly-frowned upon by the followers of God? Could it even be that the skill is a flaw created by this very godly being itself?
This episode provides some clues as to what the answer is -- mostly through Yuri’s sudden interest in killing all the wielders of the skill, which makes it seem like there is much more to the skill Taboo than the description details.
It is still unclear in So I'm a Spider if only creatures and monsters are the ones who can acquire the Taboo skill. What we know for sure is that killing your own kind is the condition that must be met before manifesting it. Wakaba acquired it early on in her awakening, and Fei developed the skill after protecting her friends from the Earth Dragon. The skill has not proven to be much of a threat yet, other than giving them advantages over their own kind. But neither character has utilized it for their own benefit, begging the question: why is Yuri so motivated to find wielders of the Taboo skill?
Yuri is a religious enthusiast in the human group, The Word of God, and it's revealed in Episode 5 that their motive is to become strong enough to be able to hear the voice of God. Yuri claims to have been able to hear the voice on a daily basis, and even characterizes God as a woman by referring to her as "she." The reincarnated humans that hear the voice of God believe that she is the one responsible for their reincarnation into their new world.
Yuri claims that those with the skill Taboo are classified as taboos themselves by the will of God. Yuri is also very nonchalant about her desire to kill all the wielders of Taboo, her demeanor being almost sociopathic as she talks to Shun about uncovering all the imposters among them. Fei overhears the conversation, and can’t help but tremble in fear knowing now that the followers of the Word of God will kill her the moment they find out about her Taboo skill.
Luckily for Fei, and even Wakaba, one needs the Appraisal skill in order to see another creature’s stats. Shun and Wakaba are the only ones that have the Appraisal skill at the moment, and it seems like the manifestation of the skill itself is pretty rare. That small detail only protects Fei for a moment, but if someone was to uncover her truth, that would definitely be used against her, and potentially as blackmail to get back at Shun. But that still doesn't answer the nagging question: why is Taboo so hated by the followers of the Word of God?
Alongside all this, Episode 5 also showcases the importance of developing skills in general, even proving that skills get more advanced with each level-up. The Taboo skill may not have benefited its wielders much as of yet, but the possibility of the skill developing into a more powerful entity is not out of the question. It is safe to assume that the Taboo skill can potentially develop into one that can even hurt God? After all, what bigger Taboo is there than inflicting damage on God, right?
Whoever ‘God’ is, it's very possible that Taboo poses a potential threat to them directly, which is the only explanation thus far as to why she would want her followers to rid the world of it. It could also be that Taboo is merely a flaw of another skill indirectly created by God, and God wants a world filled with pure beings that are not marked by sin. Regardless, the mention of both God and Taboo is starting to link the human reincarnations to a greater purpose, and their internal turmoil is only beginning to brew.