Ok I got a theory… and that is this guy got absolutely nothing to do with this specific shadow and the actual host is lemus… from what we know shadows typically have personalities and appearances the host view as “ideal”.
Lemus has shown to have low self confidence due to his body type and asocial attitude. Heart taker has a tall, slender, and overall “handsome” body, well adept to talking to girls (even if most of it comes from hypnosis) and it was even pointed out they had similar hair to lemus.
Most strikingly is the attitude of “why do females always choose trashy delinquents” pay attention because he also refers to him as “womanizing scum”..almost like the host has a vendetta against him specifically as they don’t respond at all to the other guys being healed only Adrian and what would you know, lemus had contact with the very same dude, and what did he do to lemus?
Told him to his face that the girl he was interested in doesn’t like him and to stop trying after pushing him around (ch 16). And this kinda a stretch but remember the octopus in chapter 17, heart taker supposedly had a “plan” sending it to the pool, and I think that plan was actually just acting on lemus’s desire for fan service.
And atleast we know shadows can CREATE voids of various strengths when heart taker created that bug void, so it’s entirely likely those voids could be direct manifestations of the host’s emotions thus a part of the shadow itself. Taking that into account if the octopus was a Part of heart taker it’s likely the host WAS at the pool during the void attack.
Lemme know what yall think but my thought process leads to lemus as the prime suspect rn.