Silencer is an etremely fun hero to play. He can get kills early game with his first and third ability to make his second ability do more damage late game. His Intelligence gain is like Pudge's Flesh Heap, or Legion's Damage Gain. You don't have to get the kill to take the intelligence, just be near them. Remember, you don't just GAIN intelligence, you STEAL IT AS YOU LAUGH AT THERE COLD LIFELESS BODY. If you take enough, they won't have the mana to cast spells, if they are a big enough nuker.