From Warhammer 40k - Lexicanum
Deathwing Strikemasters are specialized Lieutenant ranks, in the Dark Angels Chapter's Deathwing Company
To earn such an esteemed rank, members of the Deathwing must carry out deeds of enormous bravery on countless battlefields, honing their skills as warriors and leaders. In battle, Strikemasters guide their Deathwing brethren with skill and pride, as they bring death to the Dark Angels' enemies.
- 1: Codex: Dark Angels (9th Edition), pg. 67 — Datasheets