Firstly, Ronan was given a strict order from Kanavan to defeat Gaikoz. He was recommended to seek assistance from the Grand Chase at the Gorge of Oath.
At the castle, Lire says that Gaikoz lost a lover when a war (it was not stated which one, though it was most likely the one between Serdin and Kanavan) broke out, and he died from a trap. Arme is pitiful towards the fallen knight, and Elesis states that the tragedy made him a monster.
Gaikoz himself admits he works for Kaze'aze, who is seemingly building a "bright future" supposedly full of pain and death. Ronan shortly joins the battle, and the ghost knight is slain. Ronan thanks the group for their deeds.
Gaikoz's attacks are that like a ninja and samurai. He occasionally teleports to a party member while accompanied by a "ching" sound to attack them from behind, before sweeping his sword to hurl 3 rocks. He can also hurl the rocks without teleporting. When players are far away, he will often generate two ranged energy waves has infinite range in front of him. Sometimes he will do a dash attack. Finally he has a Danger attack, where he rapidly attacks the area in front of him, covering it in calligraphic writings that, if not dodged, will usually kill players who pose weak defense and/or vitality; Gaikoz is invincible throughout this attack.
He has two Ghost Bladers guarding him, and he is capable of summoning more if any die.
Gaikoz retains all of his attacks in Gaikoz's Castle. He is more dangerous in the sense that he is more likely to perform his teleport technique when attacked.
In the Sanctum of Destruction, Gaikoz becomes a Vengeful Gaikoz, becoming more powerful. Up to four can spawn.
He has three new attacks: He can throw weaker but directional energy waves in an arc radius in front of him, and two Dangers where he either makes a unique but powerful frontal slash or he dashes and slices at strong damage and speeds, cutting all in his linear range.
- Throughout Bermesiah, excluding Trial Forest and Trial Tower, Gaikoz appears from the Boss Gate.
- Gaikoz is the second server to be made upon the Northern American server of Grand Chase.
- He did not join Kaze'aze merely because he wanted to, but rather, joined her to get revenge for the lover he lost.
- It was never specified which war he lost his lover to, but it is likely the one between Serdin and Kanavan, as it is the only war mentioned on early times (the Dwarf/Elf and Kounat/Demon wars on Archimedia are obviously out of the question as Gaikoz was introduced and the wars occurred long before). However, he would have already known Kaze'aze was behind his lover's death, unless of course, Gaikoz was manipulated.
- Lass' 4th Job, Striker, may have been inspired by Gaikoz, as the ability to 'switch' behind an opponent and rush forward with a powerful cut was first displayed by Gaikoz. The weapons that both Striker and Gaikoz use are alike as well, except Gaikoz's holds it with both hands.
- The Japanese symbol on his flag doesn't seem to read anything significant, as the letter simply means an "i" (ee) sound.
- When he uses his Danger Attack, a Japanese symbol appears on the circle meaning "Death" (?).
- When he uses his Danger Attack, Gaikoz can be seen moving around. He makes almost the same movement as his pet; "Assault Slash". This is also similar to the Prime Knight's 3rd rage skill: Raging Unlimited Blade without the swords.
- Vengeful Gaikoz's Dash "Danger" Attack may have been based off of the Elsword character Raven's Hypersonic Stab.
- There is a pet modeled after Gaikoz, named Squire Gaikoz.