For me it's Enigma:Basically Enigma have ONLY team purpose and of course it's "Black Hole"
Back to the topic, there is no really worst hero in DotA, but some are for sure weaker than others.
Sanctos is worst dota hero
20:24 THELOVEBELOW [All] everytime you kill es you save a unicorn20:30 jeandarc [Allies] an*20:33 jeandarc [Allies] learn english