Punisher vs The War of the Realms
What if Castle was able to properly prep, and fight the war all by himself? Say, an entire year to prepare.
All of Midgard is at his disposable. He can lay traps, set up fortifications, access all the crazy stuff he normally has access to, and access to anything he's normally aware of and can reasonably obtain with no one guarding it. He is literally the only man on earth, so no worries about civilians.
Who wins?