Odd Spd Wave?

Why not look at the datamine?

https://fireemblem.gamepress.gg/datamine/feh-datamine-091318-nohrian-dusk

Laevatein: Searing Steel
The second princess of Múspell, the Kingdom of Flame. She sees herself and the blade she wields as one and the same, and keeps her emotions in check.
VOICE: Sarah Williams
ILLUST: Maeshima Shigeki (前嶋重機)
Internal Name: レーヴァテイン味方 ("Reevatein Mikata")
Internal String: LAEVATEIN_MIKATA01
(Datamine Note: Laevatein will come with the skills Laevatein, Swap, Fury 3, Atk/Def Link 3, and Odd Spd Wave 3. Fury 3 is unlocked at 4 stars.)

Laegjarn: Sheathed Steel
The eldest princess of Múspell, the Flame Kingdom, and Laevatein's older sister. A general who leads Múspell's army with dignity.
VOICE: Alicia Stratten
ILLUST: Maeshima Shigeki (前嶋重機)
Internal Name: レーギャルン味方 ("Leegyarun Mikata")
Internal String: LAEGJARN_MIKATA01
(Datamine Note: Laegjarn will come with the skills Níu, Bonfire, R Duel Flying 3, Chill Atk 3, and Distant Guard 2. Chill Atk 3 is unlocked at 4 stars.)

Helbindi: Savage Scourge
Rough and tumble general of Múspell, the Kingdom of Flame. Came from nothing and rose through the ranks thanks to his talent in battle.
VOICE: Raymond K. Essel
ILLUST: Maeshima Shigeki (前嶋重機)
Internal Name: ヘルビンディ味方 ("Herubindi Mikata")
Internal String: HELBINDI_MIKATA01
(Datamine Note: Helbindi will come with the skills Býleistr, Vengeance, G Duel Infantry 3, Guard 3, and Infantry Pulse 3. Guard 3 is unlocked at 4 stars.)

(Datamine Note: Yes, every single hero has unlock rules for 4 star rarity. This is mainly used by the game to determine the skill levels for enemy units in Training Tower, lower-level Tempest Trials, etc., and is not an indicator of whether a unit will demote or not.)