Mythic Heroes: Idle RPG (Guardian 77 - Genbu)
Lubu +30 / lv 280 / Infinite II vs Guardian 77 guardian boss.
The boss battlle took so long to happen, as I was gated from it. I lacked the combat power for me to even be able to challenge the boss. After acquiring enough star dusts, I was able to lvl up my 5th hero to lvl 260. Thanks to the game's sync-ing my guardian heroes all lvled at as well, giving me the needed combat power to challenge it.
Being gated from even challenging the stages I think is going to happen every time now as I try to climb up. Nuwa's healing ability im sure helped me a lot to get there.
To those challenging him, I wish you luck, he seems pretty durable.