That what we know about Lord Krishna supposedly took birth and died violently are actually his lilas (play, pastimes), and not real birth and violent death. Lord Krishna is just paramatma, and He is not a jivatma.
I explained what is lila, ie pastimes of the Lord in my post at https://hinduism.stackexchange.com/a/15067/2790
That Lord Krishna and his brother Balarama were not ordinary humans or jiva souls is clearly seen in the Bhagavatam verse 1.1.20 where it is said that they were just masked to look like ordinary humans, because they were the Supreme Lord (bhagavān):
kṛtavān kila karmāṇi
saha rāmeṇa keśavaḥ
kṛtavān — done by; kila — what; karmāṇi —
acts; saha — along with; rāmeṇa — Balarāma; keśavaḥ — Śrī Kṛṣṇa;
atimartyāni — superhuman; bhagavān — the Personality of Godhead;
gūḍhaḥ — masked as; kapaṭa — apparently; mānuṣaḥ — human being.
Lord Śrī Kṛṣṇa, the Personality of Godhead, along with Balarāma,
played like a human being, and so masked He performed many superhuman
If it was a Leela then everyone including Radha, Balram , Arjun , Gandhari was playing his or her role in the Leela.
In fact we are also playing a part in Leela but we are unaware of it.
Although it is true that a jivatma can play a role in the lila, it is important to understand that it is the Lord's lila and not our own lila. The difference is that the Lord's lila is played according to his wish, and not according to our own will. If the lila would be our own, it would be played according to our own will, but this is not the case because we are not the controller of the lila. However, the Lord is the controller of the lila. So it is not correct to say that the Lord's participation in the lila is like our participation in the lila because there is a huge difference.