Hello,players.Welcome to Atlantica Online.
I'll start by posting some Pros and Cons to the witch.If you have just started playing a witch or are planning on playing a witch,then read this portion.

Pros:
Flying - cannot be hit by melee attacks or cannons. This makes witches one of the best merc's to use a scroll on.
High MDef - when combined with flying, the witch can act as a 'magic filter' to whatever you place behind it... meaning placing a high defense/low MDef merc behind it can be a very effective strategy. This is also important as the melee units can only hit the Witch with magic attacks anyway.
Meteor Strike - Biggest damage to entire enemy party, and one of the highest single-hit skills in general. Instant and 1 activation to do the damage.
Dodge Rate - High dodge rate aids survivability.
Mana Trap - the only way to stop brutal/seths (Atlantica Gold).
Mana Recharge - PvE this can be extremely useful for those mercenaries with passive skills that eat up their mana quickly.
Mana Drain - PvE can be somewhat worthwhile for damage, PvP potentially worthwhile to drain melee mana.

Cons:
Flying - does not stop enemies from attacking the mercenary behind the witch, an aspect many noobs fail to realize but many higher end players both exploit and occassionally fail to take in to account defensively. I've seen many of monks and shamans lose a huge chunk of their health, or even die, because they forgot that the witch in front of them does not stop attacks.
Low Defense & Vitality - They go down extremely quickly to ranged attacks, or regular staff attacks from magic mercenaries.
Meteor Srike - a whopping 500 AP cost, and 5 turn cool down. Effectively leaves your witch useless for 3-4 turns afterwards.
Mana Trap - an enemy would either have to not care, or be extremely stupid to trigger this skill. In the end all it can do is drain mana.
Mana Recharge - PvP it is almost completely worthless. By the time any merc would run out or be near out of mana, the match would probably be decided by other factors.
Mana Drain - PvE the mana loss is pretty much worthless. PvP the damage isn't good enough to be worthwhile, and the mana loss isn't enough to dent the majority of the people you'd want to drain.