Was just testing zed on SR in the jungle, went E first but much to my surprise it did no damage to creeps, minions and enemy champions. No damage, no slow debuff. Until ranking W, E will do nothing other than a spell effect and consume energy.
Repro steps:
1. Rank E
2. Never rank W
3. E never does damage nor applies a slow
[Game][Major][Zed's E does no damage until W is ranked]
Repro steps:
1. Rank E
2. Never rank W
3. E never does damage nor applies a slow