Stage - Battle of Ruxukou
Difficulty - Hard or Chaos
Character - Ling Tong
Capture the base Lu Meng indicated within 5 minutes and 40 seconds, then capture all Wei bases afterwards.
Defeat Xu Huang.
Head to the bridge and defeat Zhang Liao.
Capture all the bases highlighted on your map.
As requested here's the unlock guide for Ling Tong's 5th weapon "Raging Winds" if you have a request feel free to ask and I'll do my best.
For more Dynasty Warriors 8 5th Weapon Guides, check out my Koei Warrior Playlist:
Dynasty Warriors 8 Secret 5th Weapon Unlock Guide