For the mechanically skilled player, Invoker is the ultimate 1v6 tool. In Dota 1, Invoker feels significantly more dominant because many players struggle to track his spells in the older engine.
A complex but rewarding build that focuses on the Quas path for sustainability and control, often used by high-rank players to dominate early and mid-game skirmishes. Build Strategy by Character Dota 1X6 - The Actual Strongest Build
Here are the top picks for a 1x6 scenario in classic Dota 1: