The forces arrayed against you are mostly intimidating in the sense of their ability to protect and in some cases heal themselves, so you’ll do well to split up in the three directions you need to go, and gang up on each enemy one at a time. Twenty turns may be a lot of time, but this battle area is positively huge, so while it may seem a good idea to all go in one direction at a time, there’s a chance you’ll fall short on time before knocking out all the enemy pokemon that way. Keep in mind that Kai, the only one with a Fire pokemon, is across the map the short way, so you will likely need to send any water-types in that direction.
Keep a close eye on the boulders as well- while they don’t do much damage individually, it can quickly rack up a lot of tens and teens, and will seriously compound any injury Ujiyasu’s forces manage to inflict. This can leave you alarmingly vulnerable if you leave your pokemon in straight lines.
There are also a few destructible rocks on the battlefield, which contain the usual items- potions and small amounts of money.
Once you’ve made your first move, Kai enthuses that you’re attacking, and moves her Pansear out to smack a rock- take care that you haven’t left anyone too vulnerable to falling boulders.
On an amusing note, the enemy will try to knock the boulders into rolling downhill even if they aren’t there anymore when the pokemon arrives, so kicking a few rocks down on your own forces in particular places can actually be advantageous, reducing the damage you take overall. Keep an eye on the terrain as well, because there are some interesting shortcuts for maneuvering about the battle map which aren’t immediately visible.
When you’ve knocked most of their forces down, Ujiyasu and Kai will hold a short ‘cheer discussion’, preparing to apparently pull some major force on you- but it’s unlikely you’ll ever discover what, as they are likely to be defeated in short order afterwards. On knockout, Kai compliments your power, and Ujiyasu complains that he can’t keep up anymore.
After the battle ends, Kai.... explodes, apparently, her hair inflating to several times the size of her own body. Ujiyasu just gripes however, wondering if maybe he’s getting old and that’s why both Nobunaga and you have been able to defeat him. Reluctantly, he gives up his castle to you. When Oichi inqures as to what he’s going to do, Ujiyasu explains that he is part of Nobunaga’s army and thus has to return to his superior now that his own castle is taken from him. He doesn’t care for Nobunaga, apparently, but for whatever reason he believes this is his only option. Bidding you farewell, Ujiyasu mutters something about hoping you become strong enough for something... and then leaves midsentence.
