Sizemore seems to have been Parson's first friend in Erfworld. The two respected each other right away, something unusual for Sizemore. Sizemore's attitude toward Parson suffered when Sizemore was ordered to kill enemy units, but Sizemore seems to have forgiven Parson.
Sizemore enjoys learning new ideas and performing new tasks, as long as they don't directly involve croaking people. He therefore appreciates Parson's capacity for suggesting ideas and activities which are new to Erfworld. He knows that associating with Parson is likely to increase the rate at which he levels. But he is also apprehensive about Parson's capacity for mass slaughter. While Janis helped him come to terms with the death toll produced by "uncroaking" the volcano, he knows he may find it harder to forgive what Parson makes him do in future battles.