I think people overcomplicate how the 2 heads deal works.
As far as I can see, both of the heads can do whatever the body is able to do. So they share all skills and techniques. But since the right one was here first, it just kind of gets more control over the body by deafult.
As far as the manga showed us, I think left head just jumped to casting spells, especially during the hero fight (Iriusha was even worried his partner spams healing too much and he runs low on mp), so they kind of just let the left head cast all the spells, because
A: It gives right head more time to think
B: It gives left head something to do
C: It's just a good distinction narration-wise, having one entity with basically two entities within itself is easier to write, if they have completely different personalities.
I can't get over the fact, that this kid lived the Mantikora. Like, how do you live getting pierced through YOUR SPINE AND GUTS, SHE HAD A LITERALL HOLE IN HER BODY, HOW ARE YOU EVEN ALIVE?!
I'm also thinking that the author isn't really writing characters off. Yes, the cat girl and bunny seem to have a nice afterstory, and there really isn't a reason to bring them back, but all the other characters? I can see the author making some sort of arc, where they all come togheter. Maybe they form some sort of a party to kill Iriusha? Our slave friend from the previous arc might try to stop them by explaining? Keep in mind, we don't really know what Iriusha action bring after he leaves.
What happened to the village he basically destroyed? What will come of the desert town? We know some sort of Priestess is now somehow involved, but there's no human world POV we can attach ourselves too.
It's kind of like the spider isekai. Characters we leave behind are either dead, or will matter when the story needs them again.
I can also spout out pure nonesense and author doesn't think about the larger picture at all and I'm an idiot for getting my hopes up for some sort of grand finale arc.
