Today I've beaten the shitass Guardian monkey.
Later I met him again with his partner and he killed me, but I'm planning a rematch very soon.
>>359238Mr. Tin-Tin-Tin?
I beat him even before
>>359137, when I was exploring the gun people area.
It's literally the easiest mini boss that I've encountered (for now).
Spam L1 when he attacks, wait a moment, jump two times when he's making a dangerous attack, reapeat until he's dead.