Mother Brain is supported by three Displays, which will constantly heal her for 1000 HP, meaning it can be difficult to deal enough damage to defeat her despite her relatively low HP. She has a Shadow-elemental laser attack that hits all party members. Defeating all of the Displays will cause Mother Brain to go berserk and unleash aggressive party-wide damage.

The Displays are susceptible to all status ailments, so Hypno Wave, Provoke, and Boogie can be great assets. If you can't disable the Displays with status effects, but can't deal damage faster than they can heal it, try killing two of them and leaving only one up to slow their pace. Unleash your best single-target or AoE techs against Mother Brain (most AoEs should only hit her and the Display directly behind her) and she should go down quickly.