Requesting a spar against the four other trainees in his group, Aldrin was naturally mistaken as an arrogant bastard, especially by Clark.
As soon as Janet granted his request, Clark produced a real spear – not a byproduct of his Concept – as he lunged towards Aldrin.
"Just because you won once or twice and hailed as the strongest trainee of ours doesn't warrant you to be this arrogant! Allow me to remove that smug expression on your face! Also… leave Irina alone!"
Although his first words were valid points, his real thought still spilled out in the end. The guy was still too obsessed over his childhood friend who was more troubled than flattered by his affection.
He picked a spear as his weapon and another spear as his Concept. That's because of the Spear Art he trained from a young age. The Energy Refiner Lineage he hailed from was master of the spear. Picking their Concepts that could aid that certain Spear Art.