The ignition system is a system that will boost certain aspects of your character depending on how high you build its level, which is done by killing mobs. Killing white named mobs will increase you meter faster. If you log off, the system is reset for that specific character.

*note: image is from a product manager, so the hp/mp is extremely unnatural*

What the different colors mean:

Level	Picture	Effects of use	Buff time
Level 1 (green)		Physical and Magical Attack boosted 100% (normal hits and skill hits are affected)	2 minutes
Level 2 (yellow)		Physical and Magical Attack boosted 200% (normal hits and skill hits are affected)	2 minutes
Level 3 (orange)		Damage output increased 7 times (normal hits are affected)	1.5 minutes
Level 4 (red)		Damage output increased 10 times and earn 2.5 times SP (normal hits are affected)	1.5 minutes
Level 5 (purple)		Damage output increased 15 times and earn 2.5 times EXP (normal hits are affected)	1.5 minutes

Stage 3, 4 and 5 Ignition buffs are so powerful, you cannot earn more Ignition until they expire (1.5 minutes).

Information adapted from here.