Guide: Farm Xenolord Ultra in 5 Mins or Less With Old Pals 15 Slots Default Damage

So it turns out Paladius is really good now. I always get 4-5 minute kills using this strategy and it's very reliable! What you'll need:
2 Mount Frostallions, 4 Gobfins (if you want, player damage isn't too relevant here)
40 4* 60 Soul Frostallions or Bastigor (Non-Alpha is fine) Legend / Muscle (or Diamond Body) Demon God / Serenity - I use Frostallion but Bastigor is probably better due to its signature moves
Holy Burst (Innate) Skill Fruits: Diamond Rain, Icicle Line
30 4* 60 Soul Paladius (Non-Alpha is fine) Legend / Muscle / Demon God / Serenity
Holy Burst, Absolute Frost (Innate) Skill Fruits: Air Blade
Max out your base defense and attack upgrades
Carbonara on everyone (20% Defense) or Cheeseburger (20% Attack), either one is fine - Healing pots don't matter, Xeno Ultra kills things in 2-3 hits

You can go with all Ice Pals if you want, this is just my preferred method.

Strategy:
When Xenolord is alone, Frostallions are out
As soon as you see it summon adds, swap in to Paladius, whose Absolute Frost skill freezes and clears out the entire battlefield of all adds. You might die more or less than me depending on gameplay. Enjoy!