Seducer is a Void affinity champion from the Undead Hordes. Seducer can offer team utility in almost all content in the game due to a 4 turn cooldown Block Debuffs on his A3. This ability will prevent your team from taking the worst debuffs dished out by the Dungeon, Faction Wars, and Doom Tower bosses. Seducer also has an AOE decrease attack debuff on his A2 that can reduce the damage your team will take from dungeon waves. Seducer is also a defence based champion and therefore easier to keep alive and possible to make into a tank to help keep your damage dealers alive.
Make sure you build him with enough accuracy to land his debuffs and a healthy amount of speed and defence. It is also possible to build Seducer in a Stun set for additional crowd control.
Seducer has enhanced abilities when paired with Temptress from the same faction. This is fairly rare within Raid.