Who is Xilonen?
Xilonen is a Geo Support Character. She is essentially a counterpart to Kazuha. While Kazuha offers grouping, Xilonen instead offers Healing and Multiwave Res Shred.
She accomplishes this by interacting with her Source Samples generated by Her Elemental Skill.
Elemental Skill + Source Samples
Xilonen always generates Source Samples of the Available Elements in the Party.
After using Xilonen's Elemental Skill she will enter a Nightsoul State. When Xilonen Attacks enemies in her Nightsoul State, If 2/3 Source Samples are Not Geo Xilonen's Nighsoul State will end after 2 Normal Attacks and will debuff all enemies in a 10m Radius with 36% Resistance Shred for the corresponding Elements
TLDR 2PHEC + QEN2
Source Sample Generation
Pyro=Pyro Hydro=Hydro Electro=Electro Cryo=Cryo Geo=Geo Anemo=Geo Dendro=Geo
Elemental Burst
Xilonen's Elemental Burst has 2 effects depending on the State of her Source Samples When she has 2+ Non Geo Samples her Elemental Burst will provide Single Target Healing for 12s
When she does not. Xilonen's Elemental Burst will do additional Damage
Energy Recharge + Talent Priority
Eskill > Burst
Xilonen Technically has a very Cheap Elemental Burst (Potential ER Req of 140%) but her Best 4* Weapon is Favonius Sword. Just use Fav.
Paw Patrol is Xilonen's BiS 5* Weapon But there are 2 Other Noteworthy Options
Freedomsworn and Favonius Sword
Freedomsworn is Directly Comparable to Paw Patrol with the Catch that Xilonen needs to use her Elemental Burst to activate its effect (undesirable for speedrunning)
Favonius Sword Generates Energy for the Entire Party Making it Xilonen's BiS 4* Option by Far Building more DEF on Xilonen Essentially just makes her Heal More
Artifacts
Scroll is the only set you should Ever use on Xilonen
There is only 1 exception. If there is already 1 Scroll user in the Party, Xilonen Can use Archaic Petra
Mainstat Recommendations DEF DEF Healing Bonus% (DEF is fine too)