This video demonstrates completing Pelna's combat trial in Terrelum.
vvvvvv [See Below for Explanations] vvvvvv
The combat trial focuses mainly on "staying on the platform while defeating 2 harpies".
Harpy has 3 attacks:
- Swoop, high knockback, but easy to dodge by jumping away
- Rock/Bomb Throw, decent knockback, also easy to dodge by jumping away
- Feathers, low knockback, so you may tank this attack rather than dodging
Harpy is weak to explosion and you can defeat them with 3 hits using any explosive attacks:
0:00 Spear Bomb, in conjunction with Concentrate and Temperance
0:32 Treble Shot with Liag Mode (Steam-exclusive).
See this post about Liag Mode:
/ pc_v125a_join_a_brand_...
Good luck!