segnales are a great pvp character type class...AFTER lvl 60. Reason for this is because at 59 you get Curse Field which is easily one of the best AoE's in the game. HOWEVER you're going to have it tough because you have to play the role of healer/buffer and also attacker once you get Curse Field. Your other main attacks will be Blood Hit and Evil Crow. You want to get all your buffs up. I would say lvl up your AoE buffs. Also get your Hyper Heal up and Fast Heal. and of course...resurrect. All of your healing/buffing skills should be first priority. It's the whole reason segnales get invited to teams. If you cannot heal and buff then you are useless. Even with Curse Field being one of the best AoE's in the game it's only one attack and has a relatively lengthy cooldown rate. The general rule of thumb is this.
Azure Knights and Bagis are the tankers for teams and at late levels they also do good dmg
Mages are your dmg AoE dealers and can also tank.
Segita Hunters also do good AoE dmg but it's not close to a Mage's and their defense sucks.
Segnales are healers for the team.
Summoners aren't used for much of anything except for their pet when doing train runs...and at late levls when they finally get their cosmos powers then they're useful again.