Shaman is a Force affinity epic from the Orcs faction. Shaman is the first free champion you will get as a login reward. Once you log in for 7 separate days you will get this epic to work on. Shaman is not particularly strong however will help you in the early game Arena as a champion that can revive one of your champions with an added shield.
Later in the game Shaman is still useful but only really used in Faction Wars to ensure you get 3 stars on levels, reviving fallen allies.
If you are using the A1 to remove buffs you will need accuracy in her build. I wouldn’t recommend this, preferring a defensive build with good speed. I wouldn’t take Shaman past level 50 and do not see a need to take her masteries to tier 6 or the need to invest many books/tomes into her.