The Solitary Suanni is a formidable Field Boss introduced in Genshin Impact with the version 4.4 update, located in the Chenyu Vale within Liyue. Here's a detailed overview based on available information.
Image via HoYoverse.
The Basics
•Appearance: Design: The Solitary Suanni appears as a majestic creature with elements symbolizing both Anemo and Hydro, reflecting its dual elemental nature. It embofors the mythological Suanni, a creature from Chinese folklore often depicted with a lion's body and a dragon's head.
•Lore: Legends from Chenyu Vale speak of the Suanni as a creature of significant power, akin to the adepti, with a connection to both wind and water. Its presence in Genshin Impact's lore suggests a deep history, possibly linked to the region's elemental ley lines or ancient guardians.
•Location: Chenyu Vale: This boss can be found in the southern mountain area of Chenyu Vale, specifically at the Chizhang Wall.
Combat Mechanics
Elemental Phases
•Anemo Form: When in this state, Suanni might levitate, perform sweeping tail attacks that deal Anemo damage, or summon tornadoes that move around the battlefield, pulling players in for Anemo DMG.
•Hydro Form: It might engage in attacks like creating massive water splashes or waves that deal Hydro DMG, transitioning into a more water-based combat style.
Weaknesses and Strategies
•Elemental Reactions: The Suanni's dual nature makes it vulnerable to reactions like Shatter, Melt, and Swirl. Using these can remove its Frozen aura or other elemental effects, potentially paralyzing it.
•Interrupting: At certain health thresholds or during specific moves, interrupting its actions can lead to paralysis or vulnerability phases, crucial for dealing significant damage.
Strategy 
Team Composition
•DPS: Characters like Ayato for Hydro or Venti for Anemo can capitalize on its elemental phases.
•Supports: Characters like Xingqiu or Barbara for Hydro reactions, or Sucrose for Anemo resonance.
•Healer: Given its Hydro and Anemo attacks, a versatile healer like Bennett or a shield like Zhongli can be invaluable.
Tactics: cont
•Elemental Mastery: Characters with high Elemental Mastery can benefit from the frequent elemental reactions, especially during phase transitions.
•Focus on Elemental Reactions: Triggering reactions can not only deal damage but also manage battlefield conditions by countering its elemental attacks or fields.
Rewards
•Defeating the Solitary Suanni grants:
•Solitary Suanni's Whisker: A new ascension material, likely for upcoming Liyue characters or those with Anemo/Hydro resonance.
•Primogems
•Hero's Wit
•Mystic Enhancement Ore
Tips: 
•Adaptable Strategy: Be prepared to switch between dealing with Anemo and Hydro attacks. Characters that can switch elements or have versatile kits will shine here.
•Environmental Use: Utilize the terrain in Chenyu Vale, especially during its Anemo phase where gusts might push you off ledges or into walls.
•Interrupt Timing: Learn the timing for interrupting its special moves or regeneration attempts for bonus damage windows.
The Solitary Suanni, with its dual elemental nature and rich lore, adds depth to the combat system in Genshin Impact, challenging players to think dynamically about their approach to both combat and environmental interaction.
