Souleater is a lvl 30 job ability. It drain's 10% of your HP, and gives it to your next attack. Souleater itself count's as a provoke. But that's not what gives you the hate. For example:
(in Garliage Citiadel last night)
Pld was hitting the Siege bat for 10-16 dmg.
The war with the Great Axe was hitting for 36-49 dmg
Nin was hitting for gimpy 5-11 dmg
whm was curing
Drk (myself) was hitting for 67-101 dmg
Drg was hitting for 27-36 dmg
Now the Pld is already fighting for hate that can be lost by a single provoke, however If I use soul eater thats one provoke...+ 10% dmg increase. Meaning instead of doing 67 dmg and crit for 101 dmg. I was hitting for 73 - 110 dmg with normal and crit strikes. Now imagine me using a WS just as I use Souleater which can easily (depending on TP) can put me at 189 dmg+ Thats a whole lot of hate. Not to mention, everytime you hit the mob, it is draining 10% of your current hp (So no souleater will not kill you) and then the IT mob is smacking you with all its might. And it really sucks if you have beserk and last resort on, because then, your getting hit for an additional 30-50 dmg.
That is why Souleater is such a dangerous move to use. Almost not worth having, but at the same time, it has saved myself and my parties a couple of times in the past.
(Oh and PS. I did 192 dmg with drk using slice + souleater + beserk + last resort, along with +12 STR. Now imagine adding Sneak Attack into the mix?

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