Seeing as the previous guide with pictures doesn't load anymore, I've decided to make a new one myself.
Stage 1
Talk with the Chaos Goblin located in Noria, Crywolf or the Silent Map.
Use the option Regular Combination.
In the 8 X 4 Chaos storage area, place:
* 20 pieces of Broken Armor(Splinter Armor)
* 20 pieces of Devine Protection(Bless of Guardian)
* 1 Jewel of Chaos
This combination will produce a Piece of Horn.
Stage 2
Talk with the Chaos Goblin located in Noria, Crywolf or the Silent Map.
Use the option Regular Combination.
In the 8 X 4 Chaos storage area, place:
* 5 Piece of Horn
* 10 pieces of Claw of Beast
* 1 Jewel of Chaos
This combination will produce a Broken Horn.
Stage 3
Talk with the Chaos Goblin located in Noria, Crywolf or the Silent map.
Use the option Regular Combination.
In the 8 X 4 Chaos storage area, place:
* 1 Broken horn
* 3 Jewels of Life
* 1 Jewel of Chaos
* 10M zen
This combination will produce a Horn of Fenrir.
Note: No way to change the success rate.
Upgrading the Horn
Talk with the Chaos Goblin located in Noria, Crywolf or the Silent map.
Use the option Regular Combination.
In the 8 X 4 Chaos storage area, place:
* One (1) Horn of Fenrir
* Five (5) Jewel of Life
* 1 Jewel of Chaos
* One or more Level 4 (minimum), Option 4% (minimum) Weapon for Black Fenrir, or Armor for Blue Fenrir.
Combination will produce a random mix which can be one of the following:
* Black Fenrir - Horn of Fenrir + Destruction (increase final damage)
* Blue Fenrir - Horn of Fenrir + Protection (absorb final damage)