Giller had been born with a great talent for magic, high intelligence, and a natural curiosity. In some, these gifts might have been squandered, but Giller put them to good use. He studied, practised, and investigated the world around him. He sought out teachers and old tomes and rare ingredients. He learnt old, near forgotten tongues, and translated other wizard's ancient journals and arcane spell fragments scribbled on age-yellowed parchment.
He was one of the best and brightest and soon earned his place as a Wizard of the First Order. Under Lord Rahl's patronage, Giller had access to even more obscure and expensive equipment and occult paraphernalia. Nothing he needed was denied if it was within Rahl's power to provide it. Including test subjects.
Giller was quite exceptional. In fact the only thing he lacked was morality.