Onyx Black

Introduction

• Onyx is 1 of 3 Crossroad guardians in Black Purgatory dungeon.
• You will face Onyx on the 3rd Crosssroad, and groggy pattern is Harmony.
• Type: Demon, Human.

Spiral Notes Pattern

• Onyx jumps to the middle and draws lot of notes in roman numerals around the map.
• The notes then move toward Onyx in a counterclockwise spiral pattern.
• Afterward, she casts an AoE attack in the middle.
• To dodge, simple run counterclockwise away from the spiral, then run away from Onyx to avoid the AoE.

Match the Beat Pattern

• Onyx jumps to the middle and starts playing music.
• You will see red orb glow around her 3 times at different frequencies. One glow could follow another extremely quick or it can be extremely delayed.
• Then she releases 3 AoE shockwaves at the same frequency as the orb glow. So to dodge, you need to time your jump carefully to match the frequency.

Harmony Pattern

• Onyx spawns 7 notes around the map, and you will see 3 notes on top her.
• To cancel this pattern, you need to step on the same 3 notes, the order of note doesn't matter.
• Do this 3 times and you get groggy. 

• If you step on the wrong note, she will AoE attack. It's not too big so you can just run away from her.
• Any fail notes will cancel pattern and you get no groggy whatsoever.

Strategy

• She's just one of the mini-bosses.
• Patterns not too hard and relatively low HP, you can nuke.

References

Namu.wiki

YouTube - JangJiTube

Other Crossroad Bosses

Other Follower Bosses

Other Dark Knight Bosses

Final Boss