What is Heat Inherit?
The status effect of heat causes enemies to take heat damage every second over 6 seconds according to the formula

0.5 x modded base damage x (1+heat damage) x (1+faction damage) x critical multipliers

Each additional application of a heat status adds a stack of heat damage AND refreshes the 6 second duration. However, every subsequent heat proc uses the heat damage and faction damage from the very first stack applied. This means if you use a 'heat primer' with max +heat damage mods and +faction damage mods, then switch to a 'DPS weapon' with only one heat mod that can consistently reapply heat status but with damage, crit and faction mods, every heat proc will actually 'inherit' the heat/faction mods from the primer while taking the modded base damage and critical multipliers from the DPS weapon.

This interaction can also allow abilities that deal heat status to inherit heat and faction mods that they normally do NOT possess, thereby boosting their damage significantly. For example, the following abilities can make use of heat inherit:

• Gauss: Thermal Sunder (heat cast)
• Ember: fireball, fireblast and inferno
• Hildryn: Blazing Pillage
• Citrine: Pristmatic Gem
• Voruna: Fangs of Raksh
• Nova: Neutron star
• Protea: Blaze Artillery
• Excalibur: Exalted Blade (with heat)
• Baruuk: Serene Storm (with heat modded)
• Nezha: Chakram/fire walker

Example setup originally described by Dystopia:
Video: https://www.youtube.com/watch?v=9Ta_ex7MUDs
Tysis heat Primer : https://overframe.gg/build/188777/
Skana heat DPS: https://overframe.gg/build/188778/