With the second part of the 2.1 update, the character of Sangonomiya Kokomi arrives and she is a character who will have a very specific role since she is care-oriented . She will therefore act as a healer for your team. You should know that Kokomi is a healer who can heal your other characters via his elementary skill but also thanks to his burst. The latter allows her to benefit, like Barbara's E (elemental skill), from a buff that allows her to heal her teammates when she hits an enemy with a normal attack but also to increase the damage of the ghost jellyfish that she summons with her elemental skill.
The healing provided by Kokomi is based on her max HP, so you will have to focus on this stat to best heal your allies. This stat is also useful for increasing the damage she does once her elemental unleash is activated. His second passive gives him a damage bonus based on his extra healing bonus so you have to rely on this stat as well, although max HP is still the main stat.
You should also pay attention to the Tempered state (as for Barbara) which is applied to Kokomi from the use of Transcendence: Doom Omen, which can therefore allow you to be frozen if you face Cryo enemies .
In case you hope to see Kokomi as your DPS, you will have to wait for another character because even if she can be played with the 4-piece Soul of the Castaway set, she will have a significant handicap conferred by her fourth passive which grants her a 25% healing bonus but which reduces his crit rate by 100%. She will therefore be able to do damage but she will not be able to take advantage of the bonuses offered during a critical attack.
To come back to Kokomi in general, this one is a healer who can be useful to you but which is absolutely not obligatory if you already have Barbara, Bennett, Jean, Sayu or Diona.
5 Star Catalyst
Base ATK: 46
Secondary Stat: HP %
Healing Bonus increased by 10~20%, Normal Attack DMG is increased by 1~3.0% of the Max HP of the character equipping this weapon. For 12s after using an Elemental Burst, Normal Attacks that hit opponents will restore 0.6 Energy. Energy can be restored this way once every 0.1s.
3 Star Catalyst
Base Attack: 39
Secondary Stat: HP %
Obtain: Wishes or drop
When switching characters, the new character taking the field has their ATK increased by 24~48% for 10s. This effect can only occur once every 20s.
2 pieces equipped: increases HP by 20%.
4 pieces equipped: When an elemental skill hits an enemy, the attack of all nearby team characters increases by 20% and their shield strength increases by 30% for 3 seconds. This effect can be triggered once every 0.5 seconds, even if the character equipped with this artifact set is part of the team but not deployed.
2 pieces equipped: Character healing efficiency +15%
4 pieces equipped: Using an elemental skill or unleash increases healing received by all party members by 20% for 10 seconds.
Xiangling can serve as a support to activate the evaporation reaction.
Ayaka can be a good character with Kokomi by allowing access to Freeze if Kokomi uses her elemental skill to allow your Ayaka to take advantage of her Ice Breaker 4-piece set.
Lisa can be played with Kokomi to allow her access to electrocution easily through her burst.
Of course, these characters are only examples and do not constitute all of the playable characters with Yanfei but just a small representation of what you can do. Your imagination will allow you to create your own teams and test according to your preferences.