Explaining to the dinner party about the Tower of Trials led to starting work on it the very same evening, shifting to an Elemental form and calling for as many Earth-type Golems as he and the two Lesser Watchers could manage.
A section of the valley was cleared of growth, making a circle a quarter of a kilometer in diameter. At first, Cain thought that might be a little excessive, but the more he thought of it, the better it seemed. If the spell can expand the area a thousand times, this would be a two hundred and fifty kilometer area trial area. That would let the spell give them multiple targets and room to move.
How could he call it a proper trial tower if you just walked in and the target was right in front of you? That would be incredibly lame and it would favor the melee combatants too much. At this size, the targets could hide, ambush, and attack from range as much as they wanted.