Missing Christmas

You've been missing ever since you joined MI6.
It's been years and you finally return back to London at Christmas.
You're working with someone who Bond thought was dead, but you actually saved their life.
You go back to the island your partner is on and do more damage.
In the end, you both go on a killing spree, resulting in damage towards MI6's new building.
Bond targets you throughout everything and can never seem to catch you both.