The new female-demigod should also be wearing armor of some kind, just to contrast visually with the skin-and-cleavage look of Sedna and Thorny. Take this DeviantArt image as an example of what I'm talking about:

Well, here's an ide:
demigod name: The Maid
type: general
ability 1: Undying Loyalty (passive)
The maid retains a cadre of undying knights who heed her every command. When they fall in battle, they shall be reborn shortly at her side. So long as she stands, the loyalty of her followers shall never die. Increasing ranks in this skill decreases the time necessary for the knights to return to life and increases their power in battle.
ability 2: Aurora of Purity (passive)
The maid is surrounded by an aurora of light that protects nearby brutes and minions from damage, causing them to vastly more difficult to kill. This does not benefit demigods.
ability 3: Martyr
All nearby friendlies receive 50% reduced damage, but the maid receives half of all the damage blocked by this ability. The maid receives a 25% reduction to all damage she receives while in this state.
ability 4: Persistance
The maid creates a symbol of persistance. All friendlies in an area around the symbol are affected by it. Should they be struck by an amount of damage that is fatal, the damage of that attack is significantly reduced, potentially allowing them to survive.
ability 5: Great Mustering (prerequisite: undying loyalty)
When activated, the Maid's undying knights stop respawning. When all have died, twice as many are summoned instantly. These will persist until they die. Knights will not respawn above their normal maximum numbers.
ability 6: Seal of Blades
Target enemy demigod is surrounded by a prison of glowing swords, preventing them from moving, attacking, or using special abilities, but also preventing others from attacking them.
ability 7: Divine Wrath (passive)
When the maid attacks a demigod, it is marked for divine wrath. Immediately after it finishes casting any spell while under the effect of divine wrath, the demigod is stunned for a short duration and damaged for a small amount.
ability 8: Castigate (passive)
After a demigod attacks the maid, it is marked with castigation. It suffers increased mana cost and casting time for all its spells and abilities.