I've alternately heard that fearful debuff is received by players within 25m of Toth, 30m of Toth, 25m of Zorn and 30m of Zorn. I've been assuming that 30m of Zorn is the correct version, but I'm not 100% certain.
Based on my guild observations; it is 25m radius from where Toth lands. we have had ranged get fearfull at 25+ meters from zorn but toth lands towards them and is with in the 25m range. Could be wrong; we never actually set out to confrim it; we just assume to be 25+ meters from the closer one to them.