The age-old Buu debate. It's always a reoccurring debate so it's good to have its own thread! Here's how I think it breaks down:
Kid Buu
Kid Buu + South Kaioshin =
Buff Buu
Buff Buu > Kid Buu
^This alone proves that Kid Buu can’t be the strongest since he became stronger after his first absorption. If absorbing South Kaioshin made him weaker, he would be pretty stupid to absorb someone else and willingly lower his power even more
.
Buff Buu + Grand Kaioshin = Fat Buu (somehow made him weaker)
Buff Buu > Kid Buu > Fat Buu
Fat Buu splits into Evil Buu (retained most of the power and evil) and Mr. Buu
Kid Buu > Fat Buu > Evil Buu > Mr. Buu
Evil Buu + Mr. Buu = Super Buu (Made up of the same components as Fat Buu but I think rearranged so less influence from Grand Kaioshin and thus more powerful)
Super Buu > Kid Buu > Fat Buu > Evil Buu > Mr. Buu
After several absorptions:
Buuhan > Buutenks > Buucollo > Base Super Buu > Kid Buu > Evil Buu > Mr. Buu
When they removed all the people Buu absorbed, he temporarily reverted to Buff Buu and they noted that his power grew. That could mean the Grand Kaioshin inside Super Buu was still restricting some of his power and made weaker than Kid Buu + South Kaioshin.
Buff Buu > Base Super Buu > Kid Buu > Fat Buu > Evil Buu > Mr. Buu
Overall:
Buuhan > Buutenks > Buff Buu (South Kaioshin was likely stronger than Piccolo but definitely weaker than Gotenks) > Buucollo > Base Super Buu > Kid Buu > Original Fat Buu > Evil Buu > Mr. Buu