UNLOCK: Capture at least one of every fiend in Besaid.
BOSS ANALYSIS : Stratoavis has a set pattern of moves. He will Attack twice, then charge for Paean of the Heavens, which is to be used on the next turn. Paean of the Heavens knocks off 93.75% of your maximum HP (since it’s the max HP, it CAN kill), induces a Delay, and blinds, so you need to fully heal on the turn before AND after it. Stratoavis will land after losing 2/3 of its HP (hits 106,667), only using his Attack thereafter.
MAIN STRATEGY : Auto-Protect is great for this fight, for the most part, since you’ll be seeing a lot of Attacks. Auto-Med and Remedy also work well to counteract the ailments from the Paean. Anyways, this boss isn’t anything special, since you know his routine. Attack on the first few turns. Next, Defend or heal on the charging turn. Protect and Defend quarters the damage taken from Paean, reducing it to almost 23.5% of your max HP. Heal on the next turn, then just keep up the attacking.
By the by, keep in mind that the boss is vulnerable to all four types of Breaks. Full Break or Banishing Blade can get in all four at once, and Power Break at least is recommended (and Armor Break and Mental Break for increasing your damage, of course). You can also Slow the boss (90% chance) if you feel like he’s moving too much, though it’s not really needed.
ALTERNATE STRATEGY - DOOM : Like a number of bosses in the Monster Arena, this one is vulnerable to Doom. This is the essence of a desperation tactic, however, because it will take 200 turns for the Doom to kill the boss. Still, if you prefer that, go for it!
ALTERNATE STRATEGY - OVERDRIVES/TRIO OF 9999 : This boss can easily be two-turned with some abilities. If your spells from Lulu aren’t doing over 20,000 damage (like Fire and Water), then you will want Rikku to Mix Trio of 9999 for this. You’ll also want three people with maxed Overdrive gauges, with the third person (other than Lulu/Rikku) to have Entrust. Have Rikku Mix Trio of 9999, then go into the Fire Fury - you ought to be able to deal as high as 16 hits, nearly 160,000 damage. Have the third character Entrust their gauge to Lulu and repeat; you then only have to hit for 32 damage after that.
This strategy can also work with Tidus’s Blitz Ace (9 hits at best), but that has to deal at least 160,000 damage per Overdrive (nearly 18,000 damage per hit with a perfect Overdrive) for a two-use kill. You can also try two Entrusts with this strategy and deal just over 11,850 per hit to get it with three Blitz Aces.
And, of course, all these tactics work well with a 2x-2x-2x slot row on Wakka’s Attack Reels (12 hits). At that level, you’d need to break the damage limit though by dealing over 13,333 damage per hit. If you try with two Entrusts, you need only 8,889 or more damage per hit to make it. Attack Reels is rather luck-based, but it’s all a thought.