Both my last 2 Bommal bosses I tried many times manually with various combinations of champions and I lost all of the runs. The best I reached was about half of his health.
The 1st Bommal, some days ago, I gave up and put on repeat and went to sleep. In the morning I discovered that the RNG gods allowed me to win with the gold key and then win 2 more times with the silver keys. The rest were all failures.
Then the 2nd harder Bommal (today) I already prepared much better with many equipment and champion upgrades thanks to the recent Artifact Enhancement event and the ongoing Champion Training event. Despite being a lot stronger, I again lost all of the many times I tried to beat him. Again, roughly half of his life is the best I could achieve (once 40% left, once 60% left, all other team combinations were fails with more life left on the boss).
This time I fell asleep in my chair for a little bit, tired from the week. When I opened my eyes the boss had about 2-3 fingers life left and I started cheering my team, which was on low health, to "go go go - finish him" and they did. Luckily I did not stop the Auto-battle as I may have messed up something with my tired head.
The MPV I would say was Geomancer (leader = HP + damage reduction). Normally his HP burn is not recommended for this boss since it makes the bombs blow up faster but he did the most damage. Also honorary mention to Vogoth who helped heal back from bomb explosions.
My suggestion to you guys is, if you cannot win, but can achieve roughly half of his health then try putting it on auto on repeat - maybe the RNG gods will gift you also a victory! :)
