Iansan Constellation Compare C0→C6

C0 = no constellation unlocked (base character) — the reference column so you can see what each constellation ADDS.

When Iansan is in combat and is in the Nightsoul's Blessing state, she will restore 15 Elemental Energy for every 6 Nightsoul points she consumes. This effect can trigger once every 18s.

When using the Elemental Burst The Three Principles of Power, Iansan will also gain the Precise Movement effect from her Ascension Talent "Enhanced Resistance Training" for 15s. Additionally, if Iansan is off-field while Precise Movement is active, she will also increase your current active character's ATK by 30%. You must first unlock the Ascension Talent "Enhanced Resistance Training" to access the above effect.

Increases the Level of Thunderbolt Rush by 3.
Maximum upgrade level is 15.

When the Kinetic Energy Scale is present, Iansan will gain 2 stacks of Surging Force after your current active character (excluding herself) uses their Elemental Burst. The stacks last until the Scale leaves the field, and Surging Force can be gained once per Scale summoning. Whenever Iansan restores Nightsoul points via the Scale, she will consume 1 Surging Force stack and restore 4 additional Nightsoul points.
Additionally, if her Nightsoul restoration from the Scale overflows, Iansan will gain 50% of the overflow the next time she restores Nightsoul points via the Scale.

Increases the Level of The Three Principles of Power by 3.
Maximum upgrade level is 15.

The Kinetic Energy Scale's duration is increased by 3s.
Additionally, when Iansan triggers Nightsoul point restoration, if there is any overflow, she will gain the Extreme Force effect, which increases the DMG dealt by your current active character by 25% for 3s.