I feel... cold.
The Legendary Shield Frozen Heart is manufactured by Anshin and comes from the Borderlands 3 Base Game.
On Shield break:Triggers a Cryo Nova that damages nearby enemies.Heals the user for 30% of Nova damage dealt.
Frozen Heart's Drop-Rates and all Sources:
3 Epics count as legendary ingredients and may come as a result: Deadly Bloom, Supernova, Cryo Spike
The Frozen Heart from Borderlands 3 and can not be obtained legitimately. The Save Editor is the only way to get the Frozen Heart.