That song has too many ideas, really. I should have simplified it. Basically, domestic dudes, esp. homos, are always looking for drama in their day to day life. That explains the title. "Adventure.exe" suggests that you can 'spice up your life' just by running an executable file. True? Yes, it is!
Unfortunately, many domestic dudes (again, esp. homos) have unhealthy fantasies about making their lives more interesting by delving into the darker side of things. This includes deviant sexual practise, smoking, joining the army, and moving to a coastal retreat in Italy to write scathing attacks on the American way of life. [Alex: Haha, I'm guilty of a few of those.]
In the case of Japanese author Yukio Mishima, he 'enriched' his life by amassing a small force of cult followers who, led by his fascist ideals, would storm a military base. Mishima and two of his lieutenants committed suicide after they're pro-Imperialism message was expressed. Basically, Mishima was delusional about the "glory of Imperial Japan" and wished to continue the Pacific war, which killed millions of Chinese and Korean people and everybody knows about it.
Tonnes of young homos look to Mishima's writing because it's "hot". That is, "sexy". He's a great writer, arguably the best of the 20th c. Unfortunately, he's also a huge drama queen and a fascist and you get Confessions of a Mask being taught in gay lit classes and young homo minds being massaged and treated to Mishima's ridiculous self-sacrificing tendencies.
I personally would go so far as to accuse Mishima of encouraging bare-backing, even if he died in 1970, long before AIDS. He's an author who's immense talent needs to be recognized and celebrated, but I wish that modern literature would recognize what a caricature of repressed homosexuality he is, and be more critical of his 'messages'.
Anyway, so "I need an empire to overthrow" is about Mishima's failed coup. "Show you about self-sacrifice" is about Mishima's Saint Sebastian obsession. "Live my life for god-as-man" refers to Emperor Hirohito. The last stanza suggests that by all rights, a Filipino has no business dating a Mishima-worshipping homo.
That's the full story. Sorry it's so convoluted.