You could certainly speak with her for more detail! Lockwood's kind of already done that. As for what the fish can share:
— Lady Messalina appeared in the west of Akhuras and quickly congregated an army: part of it, demonic, came about with her. Some recruits are former members of the Brotherhood, now 'liberated.' And some others still are demons and humans who genuinely believe that coexistence between the living and the dead is possible.
— she has so far fought a few (minor) battles to free some undead from the Brotherhood — she has largely won, proving a natural talent for military command. Her own skill is in supernatural persuasion: it appears that, like Allison Hargreeves, she can utilise her voice to command her targets to work against each other, or even to kill themselves. This suggests that she could have perhaps forced Ephes to surrender her the Hand, using her gift, and not waiting on a vote.
— there is no precedent of her being in a large-scale alliance with humans, so it's unclear if she would honour her agreement!
no subject
— Lady Messalina appeared in the west of Akhuras and quickly congregated an army: part of it, demonic, came about with her. Some recruits are former members of the Brotherhood, now 'liberated.' And some others still are demons and humans who genuinely believe that coexistence between the living and the dead is possible.
— she has so far fought a few (minor) battles to free some undead from the Brotherhood — she has largely won, proving a natural talent for military command. Her own skill is in supernatural persuasion: it appears that, like Allison Hargreeves, she can utilise her voice to command her targets to work against each other, or even to kill themselves. This suggests that she could have perhaps forced Ephes to surrender her the Hand, using her gift, and not waiting on a vote.
— there is no precedent of her being in a large-scale alliance with humans, so it's unclear if she would honour her agreement!