I had called the Centurions there. The first iceball hits the centurion, the second however doesn't.

Approaching a Bridge Over the Khalid River


A Centurion stands here collecting the tithe for the Empire.
A Centurion stands here collecting the tithe for the Empire.

Pelthaas has arrived.

Pelthaas yells 'Help! Gulthruck is bashing me!'
You attempt to bash Pelthaas but are thwarted by his armor of thorns.
Pelthaas's armor of thorns wounds you.
Pelthaas is covered with bleeding wounds.

Your infernal power MANGLES Pelthaas!
Your flaming bite DISMEMBERS Pelthaas!
Pelthaas is gushing blood.

Your infernal power MASSACRES Pelthaas!
Your infernal power misses Pelthaas.
Pelthaas is writhing in agony.

Mystic frost manifests itself at your hands before you send it forth in a frigid explosion of snow and ice.
Your iceball MANGLES Pelthaas!
an Imperial Centurion: Help! Gulthruck is attacking me!
Your iceball *** DEMOLISHES *** an Imperial Centurion!
Pelthaas is convulsing on the ground.

An Imperial Centurion's punch devastates you!
Your infernal power MASSACRES Pelthaas!
Pelthaas is mortally wounded, and will die soon, if not aided.
Your flaming bite DISMEMBERS Pelthaas!
Pelthaas is DEAD!!

Mystic frost manifests itself at your hands before you send it forth in a frigid explosion of snow and ice.
You parry an Imperial Centurion's punch.
Your infernal power *** DEMOLISHES *** an Imperial Centurion!
An Imperial Centurion is covered with bleeding wounds.