Attacking the barbazu first and changing the the rukanyr when it is slain (and changing to the dwarves if both of them are slain, I guess). Note that I'm charging (+2 attack and -2 AC) and making full use of Power Attack.
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Also, there is something about the rake/pounce combo that I just noticed (let me know if I am wrong). Namely, I noticed that rake seems to give me two rake attacks whenever I grab a foe rather than giving me two rake attacks per round to used against grabbed foes. Therefore, if I am making a full attack and get a hold on two different foes during it (for example), I get to make two rake attacks against each foe I grab (effectively leaping from one foe onto the other).
If I have properly interpreted this matter, assume that I am using improved grab with each attack and raking. After my rake attacks, I continue with normal attacks against my foe unless I have already slain them, in which case I move onto a new foe.
If this is wrong, ignore all rolls not in bold print.
Jump Check (pounce): (1d20+33)[52]
Attack 1: (1d20+23)[33]
Damage 1: (2d8+30)[41]
Grapple 1: (1d20+35)[46]
Rake Attack 1: (1d20+23)[33]
Rake Damage 1: (2d8+20)[30]
Rake Attack 2: (1d20+23)[34]
Rake Damage 2: (2d8+20)[30]
Attack 2: (1d20+23)[36]
Damage 2: (2d8+30)[32]
If new foe
Grapple 2:
(1d20+35)[37]
Rake Attack 3:
(1d20+23)[28]
Rake Damage 3:
(2d8+20)[30]
Rake Attack 4:
(1d20+23)[39]
Rake Damage 4:
(2d8+20)[25]
Attack 3: (1d20+18)[28]
Damage 4: (2d8+30)[37]
If new foe
Grapple 3:
(1d20+35)[37]
Rake Attack 5:
(1d20+23)[38]
Rake Damage 5:
(2d8+20)[28]
Rake Attack 6:
(1d20+23)[38]
Rake Damage 6:
(2d8+20)[27]
Cleave Attack: (1d20+23)[32]
Cleave Damage: (2d8+30)[35]
New foe is implied.
Grapple 4:
(1d20+35)[47]
Rake Attack 7:
(1d20+23)[35]
Rake Damage 7:
(2d8+20)[30]
Rake Attack 8:
(1d20+23)[27]
Rake Damage 8:
(2d8+20)[28]
Hmm...If that all of that is allowed, Ugrot just unleashed some serious carnage right there.