The reason for this guide is to examine synergy strategies for invoker and how to counter his foes or atleast mitigate his weakness. There are many great guides for item builds and also performing combos but I haven't seen that many which focus on this versatile hero and how he can counter and synergize. I also believe that the best invoker is one who can play against his opponents weaknesses and with his allies strengths.
Problems in the early laning phase against
Pudge poses more of a problem in early laning than most other heroes. The reason for this is that he can hookshot you and then stun you. This provides burst damage and also allows him to score a few hits which could be the end of the line for your hero.
I find that the easiest way to handle pudge is to try to cast EMP. This drains his mana preventing the hookshot. It is still smart to play on the safe side and not rely on your crazy health regen. And as always don't stay in one place
Templar Assassin Can deal a lot of burst damage and also has a great slow. This means that she can be a difficult hero to counter lane against in the early game and will be great at focusing down your squishy body in the mid to late game. Her movement speed and her higher mana pool makes EMPing her a more difficult tactic as well.
If I am going against a Templar Assassin I would recommend boots before claws. This allows you to maneuver away if she tries to move in. I have also found that tornado is better than cold snap in this instance because you can still target her if invisible to escape. Also, the orchid of malevolence could be used since it is a staple in most invoker builds.
I admit that I have not played in the competitive leagues and that I am nowhere near as experienced as many other players but when i have played with or against an invoker, I do not see alacrity being used to it's potential. If you are doing a quas wex build, then one point in exort will let you have access to alacrity and with it the possibility of boosting someones attack speed by up to 80%. Alacrity on a bloodseeker means health and damage for the team. Alacrity on any hard carry is actually indispensible.