To unlock a character's third costume, reach level 10 with that character.
To unlock a character's fourth costume, get 1,000 kills or complete 50 missions with that character.

Unlock the following characters by performing the corresponding tasks in Story mode:

CHARACTER - HOW TO UNLOCK
Diao Chan - Beat the "Battle Of Hu Lao Gate" mission on the Five Star difficulty.
Dong Zhuo - Beat the "Battle Of Luo Yang" and "Battle of Mei Castle" missions on the Five Star difficulty.
Lu Bu - Beat Chapter 6.
Yuan Shao - Beat the "Zenith Tower" Request mission in Chapter 6 on the Five Star difficulty.
Zhang Jiao - Beat the "Yellow Turban Rebellion" mission on the Five Star difficulty.

The following Legends are located at the corresponding locations. Note - Cao Cao, Sun Quan, Liu Bei, Diao Chan, Lu Bu, Dong Zhuo, Yuan Shao and Zhang Jiao Legends can be unlocked by playing as any kingdom.

Wei
Xiahou Dun - Chapter4, "Guan Yu's Escape"
Dian Wei - Chapter4, "Escape from Wan Castle"
Sima Yi - Chapter5, "Battle of Wu Zhang Plains", room #8
Zhang Liao - Chapter5, "Run the Gauntlet"
Cao Cao - Chapter6, "Bewitching Land"
Xu Zhu - Chapter4, "Battle of Chang Ban"
Xiaohou Yuan - Chapter5, "Battle of Mt. Ding Jun", room #5
Xu Huang - Chapter4, "Cao Cao's Siege"
Zhang He - Chapter5, "Iron Armor"
Cao Ren - Chapter5, "Battle of Shi Ting", room #3
Cao Pi - Chapter 5, "Battle of He Fei", room #1
Zhen Ji - Chapter4, "Battle of Guan Du"

Wu
Zhou Yu - Chapter5, "Strategist Gathering", room #4
Lu Xun - Chapter5, "Battle of Yi Ling", room #4
Sun Shang Xiang - Chapter4, "Merging Forces", room #4
Gan Ning - Chapter5, "Battle of He Fei", room #5
Sun Jian - Chapter4, "Golden Seal", room #6
Taishi Ci - Chapter4, "Assault on Wu Territory", room #6
Lu Meng - Chapter5, "Battle of Fan Castle", room #5
Huang Gai - Chapter4, "Assault on Liu Biao", room #5
Zhou Tai - Chapter5, "Battle of Shi Ting", room #5
Ling Tong - Chapter4, "Battle of Xia Kou", room #2
Sun Ce - Chapter5, "Two Paths", room #6
Sun Quan - Chapter6, "Zenith Tower", room #10
Xiao Qiao - Chapter4, "Unification of Jiang Dong", room #4

Shu
Zhao Yun - Chapter4, "A Dou Rescue"
Guan Yu - Chapter4, "Assault on Cheng Du"
Zhang Fei - Chapter4, "Battle of Chang Ban"
Zhuge Liang - Chapter4, "Three Visits"
Liu Bei - Chapter6, "Manipulation"
Ma Chao - Chapter5, "Ma Su Rescue"
Huang Zhong - Chapter5, "Battle of Mt. Ding Jun"
Wei Yan - Chapter5, "Battle of Yi Ling"
Guan Ping - Chapter5, "Blood of a Warrior"
Pang Tong - Chapter4, "Battle of Bo Wan Po"
Yue Ying - Chapter5, "Battle of Wu Zhang Plains"

Others
Diao Chan - Chapter2, "Battle of Hu Lao Gate"
Lu Bu - Chapter6, "Black Storm"
Dong Zhuo - Chapter3, "Battle of Xia Pi", second to last map, turn left when you enter
Yuan Shao - Chapter3, "Rations Defense", middle map, upper right corner
Zhang Jiao - Chapter2, "Turbans Remnants", upper left map, upper left corne

COMMAND - BUTTON SEQUENCE
Emotes - Press LT + Up, Down, Left, Right, A, B, Y or X.
Display text message bar - Click Right Analog-stick.
Message history - Click Left Analog-stick.

A quick tip on item collection: On some Gaiden Levels just defeat the required Character or Machine then return to the city (getting the defeat message) but you can still keep the items you grabbed.

This is very useful for Liu Bei & Sun Shang Xiang's "Birds", just kill Sun Shang Xiang and don't waste an hour killing the birds just quit and get her item drops.

Use the following card combinations:

1. Cao's Influence: Cao Cao + Cao Pi + Cao Ren
2. Sun's Bonds: Sun Jian, Sun Ce, Sun Quan
3. Brother's Oath: Guan Yu + Liu Bei + Zhang Fei
4. Strategist's Reckoning: Sima Yi + Zhou Yu + Zhuge Liang
5. Turbans Sanctum: Zhang Jiao + Zhang Bao + Zhang Liang
6. Burning Love: Cao Pi, Zhen Ji
7. Young Love: Zhou You + Xiao Qiao
8. Virtuous Love: Yue Ying + Zhuge Liang
9. Devoted Love: Lu Bu, Diao Chan
10. Pure Love: Liu Bei + Sun Shang Xiang
11. Xiahou's Spirit: Xiahou Dun + Xiahou Yuan
12. Faithful Devotion: Sun Quan, Zhou Tai
13. Warrior's Generation: Guan Yu + Guan Ping
14. Princesses Dance: Dong Zhuo, Diao Chan
15. Nemesis Bond: Cao Cao + Yuan Shao
16. Iron Men: Dian Wei + Xu Zhu
17. Imperial Majesty: Four "Lord" cards
18. Poison Strategy+: Four "Wood" cards
19. Engulf Strategy+: Four "Fire" cards
20. Heavy Strategy+: Four "Earth" cards
21. Stun Strategy+: Four "Metal" cards
22. Freeze Strategy+: Four "Water" cards
23. Seal Strategy+: Four "Dark" cards
24. Disband Strategy+: Four "Light" cards
25. Ingenious Minds: Four "Strategists" cards
26. Legendary Courage: Four "Officer" cards
27. Wei Phoenix: Four "Wei" cards
28. Wu Tiger: Four "Wu" cards
29. Shu Dragon: Four "Shu" cards
30. Chief's Oath: Four "Other" cards
31. Imperial Presence: Two "Lord" cards
32. Poison Strategy: Two "Wood" cards
33. Engulf Strategy: Two "Fire" cards
34. Heavy Strategy: Two "Earth" cards
35. Stun Strategy: Two "Metal" cards
36. Freeze Strategy: Two "Water" cards
37. Seal Strategy: Two "Dark" cards
38. Disband Strategy: Two "Light" cards
39. Agile Minds: Two "Strategists" cards
40. Fearless Courage: Two "Officer" cards
41. Wei's Ambition: Two "Wei" cards
42. Sun's Solidarity: Two "Wu" cards
43. Shu's Aspiration: Two "Shu" cards
44. Chief's Union: Two "Other Forces" cards

ACHIEVEMENT - HOW TO UNLOCK
Dynasty Warrior (130 points) - Unlock all achievements.
Minnow K.O. (15 points) - Defeat first rank and file soldier.
Weaponry K.O. (15 points) - Defeat first Weaponry.
Officer K.O. (15 points) - Defeat first Officer.
Budding General (15 points) - Issue first command to Allied Officer.
Budding Strategist (15 points) - Use first Card Tactic.
Victory Toast (15 points) - Complete first Quest.
Blacksmith Patron 1 (15 points) - Make first weapon.
Blacksmith Patron 2 (15 points) - Power up first weapon.
Academy Disciple (15 points) - Acquire first Chi Skill.
Workshop Patron (15 points) - Make first Orb.
Online Venture (30 points) - Connect to Online City for the first time.
Victory Banquet (30 points) - Complete first online Quest.
Mutual Exchange (30 points) - Trade Officer with another player for the first time.
Invincible General (30 points) - Complete all Quests.
Weapon Collector (30 points) - Collect all Weapons.
Chi Collector (30 points) - Collect all Chi Skills.
Orb Collector (30 points) - Collect all Orbs.
Card Collector (30 points) - Collect all Officer Cards.
Treasure Collector (30 points) - Collect all Treasures.
Legend Collector (30 points) - Collect all Legends.
Grand Developer (60 points) - Upgrade all City Facilities to maximum.
Grand Strategist (60 points) - Use all Card Tactics.
Grand General (60 points) - Reach Level 50.

ACHIEVEMENT - HOW TO UNLOCK
Academy Disciple (15 points) - Acquire first Chi Skill.
Blacksmith Patron 1 (15 points) - Make first weapon.
Blacksmith Patron 2 (15 points) - Power up first weapon.
Budding General (15 points) - Issue first command to Allied Officer.
Budding Strategist (15 points) - Use first Card Tactic.
Card Collector (30 points) - Collect all Officer Cards.
Chi Collector (30 points) - Collect all Chi Skills.
Dynasty Warrior (130 points) - Unlock all achievements.
Grand Developer (60 points) - Upgrade all City Facilities to maximum.
Grand General (60 points) - Reach Level 50.
Grand Strategist (60 points) - Use all Card Tactics.
Invincible General (30 points) - Complete all Quests.
Legend Collector (30 points) - Collect all Legends.
Minnow K.O. (15 points) - Defeat first rank and file soldier.
Mutual Exchange (30 points) - Trade Officer with another player for the first time.
Officer K.O. (15 points) - Defeat first Officer.
Online Venture (30 points) - Connect to Online City for the first time.
Orb Collector (30 points) - Collect all Orbs.
Treasure Collector (30 points) - Collect all Treasures.
Victory Banquet (30 points) - Complete first online Quest.
Victory Toast (15 points) - Complete first Quest.
Weapon Collector (30 points) - Collect all Weapons.
Weaponry K.O. (15 points) - Defeat first Weaponry.
Workshop Patron (15 points) - Make first Orb.