Castiel died six times in and that was just two times less than Sam and Dean Winchester died.

Source: https://screenrant.com/supernatural-dean-die-how-many-times/

Collins was also a mainstay of the series, having portrayed Castiel staring with Season 4 in 2008.

Source: https://www.cbr.com/gotham-knights-promotion-jensen-ackles-jared-padalecki-reunite-misha-collins-supernatural/

Is Supernatural's Castiel Based On DC's John Constantine?

Source: https://screenrant.com/is-castiel-supernatural-based-on-constantine/

This is what leads to Crowley, Castiel, and the Winchesters teaming up in order to destroy the creatures.

Source: https://screenrant.com/supernatural-strongest-villains-ranked/