Monster Color

A monster's name will be displayed in a certain color to represent its difficulty in comparison to the player's character.

Color		Level	Experience Given	Comments
	White	6 or more below your level	None	No ex
	Light Blue	4 or 5 below your level	Extremely low
	Blue	2 or 3 below your level	Low	Little Exp. don't bother, unless for a quest maybe.
	Green	Your level or ±1	Decent	An easy solo target
	Yellow	2 or 3 above your level	Good	Good and easy experience with a party; slight challenge if going solo (for most classes)
	Orange	4 or 5 above your level	Great	Great and easy experience with a party; a challenge if going solo (for most classes)
	Red	6 or 7 above your level	Great	Great and easy experience if partied with a high REC defender or guardian; very difficult to kill solo (for most classes)
	Purple	8 or 9 above your level	Phenomenal	Great and easy experience if partied with a high level, high REC, Hard Mode or above, defender or guardian; extremely difficult (and not recommended) to kill solo (for most classes)
	Grey	10 or more above your level	None	Not worth it; run away.

Even within the same color group, experience gain for different monsters varies depending on level difference between the monster and the player. The following table shows the experience ratio gained in each case:

Monster Level	EXP Ratio	Test Values
+10 above player	*0	not tested
+1 above player	1.15	1.1655, 1.15
+0 same as player	1	1
-1 below player	0.85 or $5/6$	0.83, 0.85
-2 below player	$2/3$	0.645, 0.6666
-3 below player	$1/2$	0.484, 4.888
-4 below player	0.3	0.2903
-5 below player	.15	(9/60)=.15
-6 below player	0	0

Nighteye2 Said:

That's the xp part - but the following is also something to consider: above green, monsters get:*damage bonus on their attack*damage reduction on your hits*evasion bonus

• hit bonus
• increased critical rate

These effects are still small for yellows, but become very noticable when fighting reds or purples, especially in dungeons or map 4.