Alrighty! I really like these fights, the gimmick is absolutely genius. Props!
Leorilla is very easy, I downed him with Shadow Warrior. At the start, I stunned him, used the shield skill and used either Crit, Power/Crit, Double. After that, I just repeated Power, Double, Triple until the stun and crits were off cooldown, and repeated this until he went down. I had Cheshire Twilly/Nec-Snow-Mancer and did use both my potions though, but no real speedbumps durng this fight.
Sir Bearginion, though, oh man is he tough, but luckily, I was able to beat him on my third try. Anyways, for Sir Bearginion, I used PDL with Rotten Hardtack and Seaweed, and I spaced out the many debuffs the class has. I used Light Dragon Spirit first, then when that was about to run out, I used Darkness Dragon Spirit and healed. When that was about to run out, I used Ice Dragon Spirit, then Earth Dragon Spirit. Between these defensive skills, I used whatever offensive skills I could. I ended up having to use both the Rotten Hardtack and Seaweed, and my potions, but I did manage to get through the fight.
As for the double fight, The only way I can see on how to beat it is either using DmK or using a one-hit skill on Sir Bearginion, then proceeding with Leorilla as normal. Can't think of anything else at the moment.
Shadow Warrior is Best Warrior!