Predecessor Builds > Gadget > Abilty spam
Beginning
Start with Spirit Bead for more mana and back to base when you have 700g to buy Alchemical Rod
Use RMB as first ability for faster clearing, you also want to get it to level 2 after unlocking the other abilities for faster clearing, to level Alchemical Rod faster.
The clearing will also help you get Caustica faster, which is the key to the build. It allows you to spam abilities without needing to manage your mana.
Obelisk
This is my personal favorite crest. When managed correctly, you get 1 magical power roughly every 30sec, as well as magical power and penetration as base stats. The endless scalling works great for late game.
Another perk of it is that your Basic attack can deal up to 1000 damage to an enemy hero, when at 30 stacks.
But you may choose another crest that fits you better.