Brave Burst skill level levels up randomly when fusing cards of the same types, instead of having an experience bar like Unit Levels. The key to raising Brave Burst is by fusing cards of similar BB Skill Type as follows to a max lvl of 10:
Attack skills
Healing skills
Support skills (e.g. buff def/attack/HC/BC/Rec)
In addition, your BB lvl is reset to 1 everytime you evolve. I’ve heard that in the future BB lvl is halved (rounded downwards) when evolved in future updates. e.g. if you have BB lvl 9, you will get BB lvl 4 after evolution.
Raising a BB lvl increases the following, but does not improve activation rate during arena
Raises attack for attack type skills (~15% increment when maxed)
Increase probability of inflicting status ailments for skills that does it.
Improved healing
Increase effectiveness of buff
With the above in consideration below are some quick tips for raising your unit’s BB lvl:
Raise BB Lvl only when your unit is at its final evolution
Metal Gods, units without skills, or units with different skill types do not raise BB lvl.
Raise BB lvl before you start raising unit’s lvl as it can get very costly.
Lvl of feeder units does not matter. It’s the skill that matters. Thus farm the lower lvl quest maps that requires fewer energy for feeders. Lower lvl feeders cost less to fuse.
Using units with similar element in addition to same skill type improves success rate. Updated: There is not enough evidence at the moment to support this.
Fuse 1x card at a time for higher chance of success. Bear in mind success rate seems to drop at higher lvls. Fusing more than 1 card is suppose to increase the success rate but the rate increase seems negligible.
We’ll touch on super brave bursts next time, which are coming with 6* units in the near future. Happy fusing!