Naruto: I'll Give You a Life-Saving System, and You Can Take Other People's Lives.

[System + time travel + decisive killing + invincibility + no heroine + no licking of Konoha] Ryuudou Giyuu traveled through time and became Orochimaru, a dying experimental subject. As a result, he accidentally awakened the 'Kill the Enemy and Steal Krypton Life' system. From now on, you can become infinitely stronger by killing enemies. Step by step, carve out an invincible path. Also known as "Let your destiny become stronger, but you will defeat others?" "Friend, please stay, your ninjutsu is destined for me"