Just for the record, what I mentioned was the general possibility of draining magical/soul energy from the environment (such as what for example liches and to an extent plants have been described to do) or other beings (xuhrl-njok, what Gerald/the Withering has been doing) when he brought up soul-consumption as an ability.
(I have since also pointed out soul sizes vary by individual/species, and that only the "size" of the soul grows with magic-usage, not necessarily the reliability of your magic (although the latter is trainable, too). And other various bits, ways that souls in this world work a bit differently than voices/souls of his own setting.)

 - And before it is raised as a concern, what ASTA listed are (some of) the theoretically possible applications of such sound magic, not necessarily things that Claw himself has mastered. And what he can do is often more the result of trial and error, I think ASTA mentioned; he is obviously no molecular physicist (descriptions on this level are for OoC clarity's sake). 

Hrm... I have sort of been considering the initial titles references for players, rather than what the people are known as in the world? Aemoten's immortality is certainly one thing he is usually very reserved about, and only handful of people know of (even with Olan, Thaler, and soon Jaelnec included ... there are exactly two other living people who are aware of the fact). Etakar I am not counting in here; he is a bit of a hard-to-determine case. 

(By the way, have you extended the world? The last time I asked, the areas past relevant areas of Kirirak weren't too detailed (and Reniam wasn't even decidedly a planet or anything else), aside of Junica being somewhere west of the Yawning Gorge.)