The Dalek Warlords were daleks with a much modified casing to optimise them for killing,they fought during the time war with devastating results and were almost unstoppable,they were thought to have been sealed in the time war but in early january of 2010 two of them fell to earth near a unit base in the north of england.They apparently managed to fight against the force pulling them into the time war using emergency temporal shift at the correct moment to teleport themselves several weeks into the future,These events can be seen in the episode Hell on Earth.