Pieter was taken from Del to the Shadowlands and separated from his sister, Maria, during the Shadowlands invasion. During the time he spent in the Shadowlands, he joined the Resistance. At some point, he was captured by the Shadow Lord's forces and used for the Conversion Project. He was sent back to Del, though he was an imperfect specimen, to assassinate the king. Under the control of a carrier worm, Pieter placed a Plains scorpion in Lief's bedchamber.
The scorpion plot did not succeed, and Pieter later died when a scorpion escaped its box and stung him. He was found carrying a note that repeatedly said "the king must die". Maria confirmed that the note was indeed written by Pieter, but she did not know why he would be so bent on killing the king. Maria said after his return to Deltora, Pieter had begun to suffer from severe headaches, which were later revealed to be an indication of carrier worms.
When travelling with Lief, Barda, Jasmine, and Emlis through the tunnels under the Dead Plain in the Shadowlands, Claw, Brianne, and Gers found one of their Resistance hideouts had been ransacked. The people living there, including Pieter and several other Resistance members, had either been killed or taken prisoner. The three Shadowlands Resistance members expressed grief for the loss of Pieter and several more of their allies and friends.