Despire the incredolous power and authority he wields, the Great Priest is surprisingly not arrogant or demanding. This is shown by how he is among the few Gods who is not at all bothered by Goku's informal behaviour. He is polite to his subjects even if he commands them. The Great Priest also seems to be intrested in those who can reach levels beyond their limits and is willing to praise them.
While initially thought to have been amoral and even sadistic towards the erasure of the Universes, it was later revealed that the Great Priest was aware of and fully supported Zen-Oh's use of the Tournament of Power to test the virtue of Mortals. Hence, it can be assumed that like with Zen-Oh, the Great Priest actually had no intention of causing any permanent harm and only wanted to teach the universes a lesson on the power of wishes and why they shouldn't be used so casually and also not to take their battle power for the granted. He looked genuinely pleased and satisfied of Android 17's wish to resurrect all the Universes and openly praised Universe 7 not only for their battle power, but for their selflessness.
The Great Priest is said to be one of the five highest fighters in the Multiverse by Whis and Whis even said even he is no match for his father. He is therefore the strongest Angel in the series and is theroritically considerably stronger than the other Angels,including Vados,Supreme Kais and Gods of Destruction,as evidenced when both Supreme Kais and Gods of Destruction are terrified of the Great Priest and would immediately kneel in his presence and do almost,if not,anything that the Great Priest orders,implying he is capable of easily killing them if they dare challenge him. In the Manga,he was strong enough to block punches from Beerus and Quitela with his finger,something which shows his incredolous levels of power, and capable of remaining unfazed by Rummshi's Battle Roar.