Mortals, haunted by death's spector...

For the hardcore gamers, here are Widdershin's stats. I'll be honest and admit, I tend to delete my saves, accidently of course. So I replayed the game again using cheats. So I defeated Widdershin in a matter of seconds. Sorry Widdy...

Normal Mode
Lvl: 80
HP: 72000
P. Atk: 665
P. Def: 495
M. Atk: 545
M. Def: 495
Weak: None
Strong: None
Weight: Heavy
Basic EXP: 3921
Gald: 1000
Drop: Heal Bangle, Mental Bangle, Septanite Ore. Septanite, Elixir
Steal: Septanite
Notes: Attacks change when HP falls below 50%.

Hard Mode
HP: 113000

Very Hard Mode
HP: 200000
P.ATK: 2662
P.DEF: 2237
M.ATK: 2362
M.DEF: 2237

Attacks:
Giant Sword Slash
Throw Swords
Negative Gate
Punch Up and Stab
Eternal Finality (see doppelgängers for description/screenshot)
Second half of attacks during final battle, once his HP has dropped significantly, are physical
Sword Rain
Spin Attack
Swords Surround and Stab
Double Demon Fist
Meteor Storm
Sword Shield
Outburst

Information gathered from Namco Forums, GameFAQs, NeoSeeker.