The 2 Apostles
Reducing 12 disciples to 2 is a question of space and common in relief art. If you look closer you can see more male profiles carved into the background to represent the others in Christ’s retinue.
The 2 on the left behind Jesus are probably Apostles. They are holding palm leaves, a typical attribute found in depictions of the martyrs. The palm leaf also refers to the death of the main protagonist, drawing nearer with every step.