As Mara said, there were multiple things Clovis could actually try. If the killing intent was able to boost his ability, he first had to manifest that killing intent.
All this time, Clovis had been influenced by the killing intent helplessly. The more he got used to it, the longer he could use his Abyss Time. That was what he thought until he met Mara.
If Clovis trained his Abyss Time by getting accustomed to it, Mara's method was even crazier.
She used a method similar to that of super injection even though she hadn't received a single one in her life.
When Clovis received a super injection, he could sense the beasts coming at him as though they were trying to take over him. So, Clovis fought them in that state, which boosted his absorption rate.
Mara used this method. Instead of getting used to the killing intent, she actually dove into it, fought it head-on, and came out on top.
