As a person who mains a demon avenger, I noticed a lot of problems that demon avenger have that need to be fixed. The three most important aspects of demon avengers that need to be fixed that they lack or don't have are: enough burst dmg, critical rate%, and iframe skill.
For burst skill: Dimensional sword is meant to be a burst skill that demon avengers to use;however, looking at the damage% and lines, it doesn't consider to be a burst skill. Here's a suggestion.
Considering this skill is Lvl 30, we can change "HP Cost: 20%, summons a magic sword for 40 sec every 3 sec. Max Enemies Hit: 8, Damage: 1870%, Number of attacks: 8, The skill duration becomes 1/5 if the skill is used again while summoning, but the magic sword will spin quickly and deal 660% damage to 8 enemies 6 times" into: "HP Cost: 20%, summons a magic sword for 40 sec every 3 sec. Max Enemies Hit: 8, Damage: '2800%', Number of attacks: '12', The skill duration becomes '1/4' if the skill is used again while summoning, but the magic sword will spin quickly and deal '990%' damage to 8 enemies '10' times." Please notice that I put ' ' around the part that can be fixed.
For critical rate%, possibly we can put 20% crit rate on Desperado mastery in 2nd job skill. Demon avengers' basic crit rate starts with 25%, which is incredibly low that it is way too difficult to get 100% crit rate. Therefore, adding more crit rate is vital for demon avenger.
Lastly, for iframe skill (most important): Since demon avengers do not possess iframe skill, there's no way to survive from the snow(that heavily falls from the top with splash damage) that falls in 3rd phase of black mage from the test to be unavoidable most of the time. That snow pattern is meant to be the part where we iframe to avoid, but since demon avengers don't have iframe, demon avengers totally discrimminated from other classes that have regular iframe skill. For suggestion, it would be great to add iframe for a skill Vitality veil from 3rd job skill just as making character to be invincible for 3 times after skill is used, and extending the cooldown time to like 50 seconds from 12 seconds.
Top hard bosses in maplestory are burst meta, but demon avengers cannot deal enough damage due to really weak dimensional sword skill that doesn't deal enough dmg as a burst skill, and making survivality to be extremely low by no iframe skill are tremendous problems with this class. Therefore, this class needs to be buffed.
Thanks for reading this long post. Please notice that there's extreme problem that demon avengers have right now as shown above!