I couldn't finish 'em. Looks like this's gonna get complicated.
Captain Madison is a recurring boss in Final Fantasy XIV, fought three times over the course of Sastasha and Sastasha (Hard). He is the Captain of the Serpent Reavers, a band of pirates under Leviathan's thrall. In each encounter he flees before meeting an ignomious end at the hand of the dungeons' respective final bosses.
Sastasha (First Encounter) Edit
Captain Madison is first encountered alongside two Shallowtail Reaver marauders, with roughly 1050 HP each. The only abilities he and his marauders have are Fast Blade and Heavy Swing, which can't be avoided but cause only minor spikes in damage. Madison will flee the encounter at 50% health. Unlike other boss encounters his minions won't despawn upon his defeat, preventing the party from being able to ignore them.
Sastasha (Second Encounter) Edit
Captain Madison is once again encountered with two Shallowtail Reavers, but has picked up a couple of new tricks. He will now use the Sandslinger ability to lower the tanks Accuracy, and instead of fleeing at 50% health he will summon four Scurvy Dogs. The dogs have no abilities and very low HP (roughly 350), and can be quickly AoE'd down. Madison will once again flee once he falls to 20% HP, and leave the party to deal with the remaining adds.