Tree of Aeons - Demon Boss Battle I (assisted)

Vincent Strider was a gun for hire who made a living by killing whoever it was his clients wanted dead. But during one mission, he died in a fierce gunfight. However, death was not the end for him. Vincent found himself reincarnated in another world, facing a floating interface that flickered before his eyes.[Synchronizing Host!][Military System initializing.]Vincent found out that in this system he received, he can summon soldiers, tanks, aircrafts, and even warships! This is going to be exhilarating.

I’ll give you an opportunity—but not for free.Gates have opened all over Earth, unleashing hordes of monsters from other dimensions. Humanity stands on the brink of extinction, with only ten years left until the end of Earth as it is.With my awakened skills, Record and Time Rabbit’s Luggage, I’ve spent seventy-six lifetimes trudging through these grueling regressions. The repetition ends here, on this Attempt.But it’s unfair if I’m the only one suffering, right? So let’s share the burden.“Ah, don’t sweat it! I’ll give you a good opportunity. For what you’re getting, it’s a bargain, don’t you think?”

When the night came, there was a twittering sound in his ears, and the monster in the shadows began to move restlessly. Jason’s hungry stomach began to roar, and he couldn’t help swallow his saliva. Hunger was the best spur.

A normal high school boy with nothing much happening in his life except for...life. Every new day was the same as the one before but he doesn't really care much about it. He thought of himself as a normal high school-going boy with no clear future. Lazy, sarcastic, but kind of intelligent, he was living a normal life.Though fate had different plans for him as he met a girl who he did and did not know. The school princess was the first thing he saw when he woke up in his bed caressing his head. To any other boy in his situation, it would be pure bliss but he was worried.Why?Since she was in his house which he had locked before going to sleep. Little did he know that the girl was more than what she showed and was about to turn his entire life upside down. How will he tackle this situation? No one knows that.