The team names, Silver Blades and Dread Legion, are based off old D&D Gold Box games, specifically "Secrets of the Silver Blade"

Silver Blades
One Eyed Willy (Pirate Captain) - Eupheism for... well, nevermind.
Sir Hans Kreuger (Magic Knight) - Characters from Wing Commander Novels
Rudyam (Elementalist) - Character in the Ultima series of RPG.
Vaeregoth (Dark Archon) - Character from the Starcraft Campaign, Legacy of the Confederate 2.
Bartuc (Warlord of Blood) - A unique monster in Diablo 2, full name "Bartuc the Bloody"
Ultra Magnus (Battle King) - Character from Transformers series.
Bloody Malth (Assassin) - Villian from Ninja Gaiden.
Duke Freid (Field Marshal) - Character from the anime Vision of Escaflowne.
Dian Wei (Shodo-Pan) - Character from the Three Kingdoms novel.
Teela (Royal Guard) - Possibly from the He-Man series.
^___^ (l337 |-|axx0rz) - Emoticon, generally used by the anime-obsessed
Birdie (Keyseeker) - Character from McDonalds Ads
Mordenkainen (Loremaster) - Named after several spells in the Dungeons and Dragons setting.
Torin the Chosen (Champion) - Uber Life Hero from Master of Magic, unique because he can only be received by casting a certain spell, unlike other heroes.
Kikyo (Priestess of the Light) - Character from the anime Inuyasha.
Kerrigan (Ghost) - Hero Unit from Starcraft

Dread Legion
Zelkin (Plasma Knight) - Character from the Capcom fighter, Star Gladiator
Cadorna (Lich) - Villian from Pools of Radiance. Doesn't start ouf as a lich though.
Bastellus (Force of Terror) - Creature from the Ravenloft setting.
Khasra Redclaw (Dragon Knight) - Character from Wing Commander novels
Ad Avis (Spell Slayer) - Villian from Quest for Glory series, he first appears in the 2nd game, returning as a vampire in the 4th.
Lavarinth (Defiler) - Campaign Creations forum member.
Fangskin (Pit Viper) - Unique enemy from Diablo 2.
Zergling (Devouring One) - Hero unit from Starcraft
Kuth Kullen (Gravity Lord) - Character from the Warcraft campaign, Wanderers of Sorceria.
Anubis (Crypt Lord) - Ancient Egyptian God.
Ashura (Night Stalker) - 
Sea Clamp (Tidal Lord) - Character from Transformers.
Baghtru Skullsplitter (Warchief) - Hero from Master of Magic.
Xanatar (Star Spawn) - D&D character?
Mumm-Ra (Obsidian Guardian) - Villian from Thundercats.
Tokka (Flame Snapper) - Minor character from Teenage Mutant Ninja Turtles
Skeletor (Burning Hell Archer) - Villian from He-man series.
Exdeath (Corrupter) - Villian from Final Fantasy 5.
xX_Azncloudstrife67_Xx (1337 |-|axx0rz) - From online stupidity, such as acting "Asian" with Azn in front of the name, and Cloud Strife, a popular character from Final Fantasy 7. 67 is there because name of popular characters are generally taken and so they have to add random numbe
rs.
Abominus (Demolisher) - Character from Transformers.
Grimace (Keyseeker) - Character from McDonalds Ads.
Dadaelis (Black Ship) - From Wizardry Gold.
Warrax (Champion of Darkness) - Hero from Master of Magic.
Tsubaki (Priestess of Death) - Character from the anime Inuyasha