Method to Acquire: Before 10 turns are up, speak to him with Lalum or Elphin in Chapter 13. However, he does not recieve a Hard Mode bonus in Chapter 13 and is a lot harder to safely speak to. For this reason, you should wait until Chapter 15 to recruit him with Lalum or Elphin. Percival and his troops appear above your units' starting point on Chapter 15 and across the top bridge on Chapter 13.
Damage - Percival cuts through enemies left and right. Don't worry that he has a low skill and seemingly has a low chance to hit, he WILL hit almost every blow.
Critical - It's especially good if you support him with Lalum or Elphin and give him a Killer Lance/Axe or a Killing Edge.
Speed - He has an almost guaranteed two hits on any enemy in the game.
Dodge - His dodge is very high with the weapon advantage and supports, but he doesn't really need that because he won't be taking much damage at any rate.
Growth Rates
HP - 75%
Strength - 30%
Skill - 25%
Speed - 35%
Defense - 20%
Resistence - 10%
Luck - 20%
Average Level 20 Paladin Percival(Hard Mode stats in parenthesis)
HP - 54(60)
Strength - 22(25)
Skill - 17(20)
Speed - 23(25)
Defense - 17(18)
Resistence - 13(16)
Luck - 15(18)
Total - 161(182)
Supports
Klein - 20/30/40 turns
Cecilia - 15/30/40 turns
Dorothy - 59/60/80 turns
Elphin - 20/30/40 turns
Douglas - 15/30/40 turns
Lalum - 30/30/40 turns
Rating - 9.4/10. Percival is the best Paladin, a good choice to wield Durandal, Malte, or Armads, and he starts off prepromoted and strong.