Let's Play Ys 8 Episode 78: The worst boss in the game
1Warning: Shortly after you kill this boss you'll enter a point of no return where the games world becomes a lot more dangerous (think sealing hollow bastion in kingdom hearts) and you'll also be cut off from the northern half of the island for a little while.
Anyways here's baselius a three phase mess of pain. Before you can even fight Baselius you have to take out his floating skull heads until you kill enough to open a bridge to reach Baselius.
Phase 2 isn't too bad just some swipes with his staff and an energy shot that fires double the amount of projectiles you expect it to fire but those skull jerks just keep spawning in infinitely.
Phase 3 he will add explosions to the arsenal to both burn and poison you. And worst of all he summons 5+ floating skulls that will attack you and after a while he will use a sacrifice attack where every skull he sacrifices becomes a homing explosive projectile that can burn you.
You may have realized by this point that Baselius does not stagger at all so you think maybe if you interrupt the spell he'll stagger right? WRONG he just does it again as many times as he wants.
Now this can be used to your advantage if you get good RNG because you can loop him into summoning the skulls and trying to sacrifice and you may be able to burst him down but you need to realize if you screw up once. Two sacrificed skulls is more than enough to kill you so it is necessary to manage your SP while killing the skulls while also being able to damage the boss who floats away from you and remember he doesn't stagger.
Anyways after he's destroyed we actually have a pretty cool room (REMEMBER TO ACTIVATE THE WARP STONE AS YOU WILL BE RETURNING HERE) and we receive a plot dump about the true nature of the tree of origins that's less benevolent than the eternian legends lead you to believe.