Hi, I have Errol and from my experience Errol needs a little bit of love to be a legendary champ. In my opinion he is now only a good single target DD but for a legendary (in my opinion) they should have something outstanding

Here my suggestions to buff him a little bit to make him a good arena champ and give him some backup utility for dungeons or even a worse option for CB.

Blazing Sword [ATK]

Attacks 1 enemy. Has an extra 30% chance of inflicting a critical hit. Has a 60% Chance to Apply a 50% ATK down (or any other debuff, or chance for an extra turn ..)

Level 2: Damage +5%

Level 3: Damage +10%

Level 4: Damage +10%

Helmbreaker [ATK] (Cooldown: 4 turns)

Attacks 1 enemy 3 times. Has an extra 30% chance of inflicting a critical hit. Will ignore DEF by 50%. Applies a Block Revive Debuff om death

Level 2: Damage +10%

Level 3: Damage +10%

Level 4: Damage +10%

Level 5: Damage +15%

Level 6: Cooldown -1

Negation [ATK] (Cooldown: 4 turns)

Steals all buffs from a target enemy, then attacks the target. Has an extra 30% chance of inflicting a critical hit.

Level 2: Damage +15%

Level 3: Damage +15%

Level 4: Damage +15%

Level 5: Cooldown -1

Aura

Increases Ally ATK in Dungeons by 35%.

Krypt King Graal

And here a suggestion for Krypt King Graal , to give him a Endgame role for CB and Dungeons

CRYPT-KING GRAAL SKILLS

Brittleness Bane [ATK]

Attacks 1 enemy. Has a 60% chance of placing a 50% [Decrease ATK] debuff for 2 turns.

Level 2: Damage +5%

Level 3: Buff/Debuff Chance + 5%

Level 4: Damage +5%

Level 5: Buff/Debuff Chance + 10%

Death Fires [ATK] (Cooldown: 4 turns)

Attacks 3 times at random. Has a 50% chance of placing a [HP Burn] debuff for 2 turns.

Level 2: Damage +5%

Level 3: Damage +5%

Level 4: Buff/Debuff Chance +10%

Level 5: Buff/Debuff Chance +15%

Level 6: Cooldown -1

Elemental Unity [ATK] (Cooldown: 4 turns)

Attacks all enemies. Places a [Freeze] debuff on each target for 1 turn if they are under a [HP Burn] debuff. Extends the duration of any [HP Burn] debuffs to 3 turns. This effect cannot be resisted.

Places a 60% Increase Defense for 2 turns on all allies

Level 2: Damage +5%

Level 3: Damage +5%

Level 4: Damage +5%

IF A3 is to strong skip the freeze

Aura

Increases Ally HP in all Battles by 33%