As Arin reaches the rest of the party, the three strange rats look at each other, almost seeming to be forming a plan. The normal rats all flee, save for one who yet looks like he is observing.
Initiative: Arin, Marcus, Mzarem, the rats, Ashe, Saxon, Vargo.
Arin has just reached the group, and upon seeing the rats, takes up a defensive position.
Marcus had said he was moving into melee, and does so, swinging at the nearest rat, but missing it quite soundly.
Mzarem then cautiously moves in to bite one of the rats, but it nimbly evades the much larger animal's bite.
On the rat's turn, all three seem to concentrate, and the runes on their backs and belly flare with magic. Both Mzarem and Marcus attack again, trying to stop the eldritch energy from forming into a spell effect, but only Marcus is successful, slashing into his enemy (7 dmg) and whipping it into the water with the end of his blade, where it slowly writhes and begins to sink.
The energies around the rat Mzarem is attack seem to coalesce, then dissipate. Mzarem looks around, seemingly very confused.
The third of the rat's energies forms about him, and he seems to be even more nimble than previously, darting swiftly this way and that, though he does not attack.
Ashe slowly moves forward, sidling in next to Mzarem and lunging forward with his rapier (threat, not crit, 5 pts), skewering that rat and sending it stumbling into the muck.
Saxon readies his sling, and letting loose a stone, narrowly misses the remaining rat.
Vargo, while you watched the rats, you got the distinct feeling that what you were looking at were spell triggers of some sort, and with spellcraft, you discern that the rat Ashe and Mzarem fought had cast invisibility to animals, while the rat Marcus slew before its spell activated cast blur. The third rat, the one yet conscious, cast a spell that you did not catch.
Thus ends round 1. On round 2, Marcus takes a 5' step forward and swings down with his bastard sword, cleaving easily through the last remaining rat and hitting the stone beneath, such was the power of his swing (12 damage).
The remaining normal rat attempts to flee at high speed, with Mzarem running in hot pursuit. The only other character who could attempt to hit the rat is Saxon, who lets fly another sling stone and surprisingly strikes it (4 dmg), easily reducing it to a reddish-brown paste.