The Resistance Leader of Inazuma is an hydro character and before unleashing her might on the enemy you will first need to upgrade the character a little. Here is the complete list of the materials needed for Sanganomiya Kokomi.
Kokomi Ascension Materials

Varunada Lazurite Sliver
Number required: 1

Varunada Lazurite Fragment
Number required: 9

Varunada Lazurite Chunk
Number required: 9

Varunada Lazurite Gemstone
Number required: 6

Dew of Repudiation
Number required: 46

Sango Pearls
Number required: 168

Spectral Husk
Number required: 18

Spectral Heart
Number required: 30

Spectral Nucleus
Number required: 36
Kokomi Talents Upgrade Materials List

Spectral Husk
Number required: 18

Spectral Heart
Number required: 66

Spectral Nucleus
Number required: 93

Teachings of Transience
Number required: 9

Guide of Transience
Number required: 63

Philosophies of Transience
Number required: 114

Hellfire Butterflies
Number required: 18

Crown of Insight
Number required: 3

If you're looking to upgrade your Raiden Shogun here is the complete list of the materials you'll have to farm to Ascend Raiden and her talents.