Deathstar Units
A Deathstar unit is a unit in a wargame that is maxed out to be as powerful as possible within the game mechanics. This is normally a massive points sink, but is insanely powerful. They are named after the death star from star wars, which is a massive (Seriously, if you don't know what the death star is get off of this site). The unit is typically maxed out by taking a powerful unit and adding one or more characters who can buff the unit even further. Normally only passive modifications are used, with short term buffs being too unreliable. Not all armies can field death star units.
Common Traits
Common traits of Death Star units include:
Huge Points Cost
Near Invulnerability
Massive damage output
As one heads into larger games, death star units have less and less impact, as opponents have more and more things to counter them.
An example death star unit
Taken from WHFB Vampire Counts
Mannfred von Carstein on barded nightmare
Vampire lord with heavy amour, shield, nightshroud, giant blade, Quickblood, dread knight, red fury, Barded Nightmare
Necromancer with Featherfoe Torc on Barded Nightmare
Vampire with Fear Incarnate, Aura of Dark Majesty, the terrifying mask of EEE, Heavy Armour, Shield Barded Nightmare
Necromancer with Obsidian Lodestone on Barded Nightmare
Vampire BSB with Razor Standard on Barded Nightmare, and Forbidden Lore (Lore of Heavens)
40x Blood Knights with Full Command, Kastellan with Sword of swift slaying, standard bearer with banner of blood keep
This set up will be pushing towards the 3000pts mark, and will need at least another thousand for core, but with it you get:
2+ armour save T4 S5(7) cavalry, with a 4+ Ward save that increases to a 1+ when faced with magic, and within there is magic than can raise the fallen, re-roll rolls to hit and wound, nerf enemies, etc. You will be ignoring all but 1+ saves with most of you're attacks. The vampire with the giant sword is able to hand any character's ass back to them on a plate, with a 1+ armour save, ASF, S8 with armour piercing ignoring all armour, and reducing the enemy to base strength and ASL. All attacks by the one group of enemies that could reliably hurt it, Monsters, are forced to re-roll rolls to hit.
If the enemy manages to bring this down (Final Transmutation, I'm looking at you) you will be out of the game however. Not just out, but the game will have raped you, beaten you over the head, stolen you're money and left. Thus, the duality of Death Stars.