The seer council is a band of Warlocks who are very strong in melee combat. They are capable of high dps and can jump onto opponent if within range, narrowing the gap for close range combat. The unit is capable of fleet of foot.
Although the seer council is powerful, it being a melee unit can be taken out easily at range. So it is key to manouvre in a way that you avoid receiving damage prior to engaging. The Farseer's spirit stones wargear has a good synergy w/ them as it heals them after taking a bit of damage to their initial hp state (if used correctly).
Use of gates can really boost their travel efficiency, however being a unit summoned by use of red, it may be difficult to have gates up. The Autaurch has good synergy as she buffs speed and allows them to heal a bit with her jump ability.
The SC can be a crippling unit to the enemy or a waste of requisition and red if counters were already prepared.