Predecessor Builds > Gadget > Magic Power Gadget (deletion zone R)

1st back Alchemical Rod. Move on to Overseer afterwards. I usually dont finish Azure Core until quite late in the game, seeing as it provides no offensive power. You might wanna do so if you find the enemy team attempting to pick you off frequently.
2nd item Overseer.
3rd item depending on the gold you have available and the enemy team. Spellbreaker can be nice, it offers a good boost to magic power as well as a spellshield, but against enemies who easily proc that spellshield (e.g. fey) you might want sth else.
Anti-Heal: Usually the enemy team has at least one champion you want anti-heal for, and with Gadget you should take care of that. Tainted Scepter is amazing for additional poke damage and your R lets you easily spread the Anti-Heal effect. Id say to get it 3rd item or later, depending on how early you find yourself in need for it.