Of course, the MC wants power, he is the muscle of the party and wishes for revenge or at least the strenght to not bend to anyone anymore but the "teacher" decides to castrate him limiting the target of his ability.
He going throught a war zone, a cemetery or a hunting field should give him that power easily but we know he will listen to her and never use that power outside the enemy/beasts he kills, even knowing the people sent with him are deliquents (wannabe rapists) with incredible high levels and fast growth and will probably destroy the country after getting enough power, and it seems like he have forgotten about the girl, even with the kingdom protecting her as she have the status she wants he should know the danger she is in with the mass of corrupt people around.
With his power MC should be able to convert the armor of someone in stats and skills if it was made using a defeated beast, wonder if the author will make him realize that or every intelligent enemy with said equipment will never have to worry about it, we know he doesn't need a fresh corpse or even a whole one, so leather glover (example) should be enough for his skill.
This isekai would be a lot simpler if he never meet anyonen in the canyon, got out alone, arrived to a country and asked directions for the tomb of a great hero/adventurer.
The level increase stats but he increase stats from absorption even at lv.1, he just need enough corpses to pile up the numbers and be able to confront a lv.100.
Only have to worry about special skills that target someone with a inferior level, that I guess he will meet and would normally be skills with limited potential in that world.