Boss 28 (Braska's Ultimate Summon)
HP (First Form): 60,000
HP (Second Form): 120,000
HP (Yevon Pagoda x2): 5,000 (initial)
The two Yevon Pagodas will heal Braska's Ultimate Summon 1,500 HP (and OD at the same time) every turn. The Yevon Pagodas' HP aren't constant. It depends on how much damage is inflicted on it to kill it. For example, if it took 6,000 total damage to kill it, it'll revive with 6,000 HP. The first two times Tidus uses the Trigger Command Talk on the Ultimate Summon will confuse it and reset its OD gauge. Don't do this yet. Save this for the Second Form because First Form's OD will only deal around 3,000 or so in damage. Either ignore the two Pagodas or kill them both. Don't kill only one or else it'll use a multiple-status status attack on one member.
The Second Form basically adds a powerful physical attack (the sword) against the entire party. Also, when the Ultimate Summon has less than 60,000 HP the OD changes to True Jecht Shot and can deal around 3,500-5,500 HP in damage. Pay attention to the battle order and heal whenever someone's HP falls below 3,500. As usual, use any Aeons if you have any left. If your party is in good shape, doublecasting Ultima, Flare, or attacking with Holy will do wonders. Don't forget to cast Haste and Auto Life on yourself so you're ready for the worst.