Here are some gender-neutral fighter names fitting the description of fierce, loyal, charismatic, and agile:

Inspired by Nature:

• Swiftclaw
• Nightshade
• Stormbreaker
• Shadowdancer
• Riverwind
• Ironwood
• Emberheart
• Skytalon
• Stonefist
• Wildfire

Inspired by Mythology/Fantasy:

• Valiant
• Rhyland
• Zephyr
• Phoenix
• Gryphon
• Seraph
• Wraith
• Rune
• Argent
• Obsidian

Inspired by Abstract Concepts:

• Relentless
• Paragon
• Maverick
• Zenith
• Vanguard
• Catalyst
• Cipher
• Renegade
• Invincible
• Dauntless

Inspired by Sounds/Words:

• Kestrel
• Talon
• Ravage
• Tempest
• Echo
• Whisper
• Surge
• Apex
• Vixen
• Renegade

Combinations:

• Swiftfire
• Shadowclaw
• Ironheart
• Stonewind
• Embertalon
• Skybreaker
• Wildfire
• Valiantclaw
• Runeheart
• Obsidianwing

This list provides a variety of options, allowing for further customization and refinement based on specific project needs. Consider combining elements from different categories to create even more unique names. For example, "Shadowtalon" combines the mysterious "Shadow" with the agile "Talon."