"Equius is a complicated and initially disturbing troll. He is a firm believer in the blood-caste system and believes one should respect those higher than them and is personally disgusted by those who are lower. He believes one is not only allowed, but obligated to boss around anyone who is lower-ranked than them and to accept and obey orders from anyone who is higher-ranked. He believes "highbloods" should act with elegance and authority and "gutterbloods" should act with crass and submission, and most importantly, highbloods and gutterbloods should not fraternize. Any deviation from this pattern (such as Gamzee and Aradia's actions) flusters him greatly. He tries ordering highbloods to order him around, but notices the contradiction."

(Taken from the Homestuck Wiki)

I’m thinking a deep, quiet voice would work nicely for this role! I’m not sure on how to get into specifics for his voice, so like with all of these roles, you can take creative liberty in voicing him.