Sir John Falstaff is Henry V's ex-BFF and mentor. In Henry IV Part 1, Falstaff taught "Wild Prince Hal" everything he needed to know about leading a life of total debauchery. (If there were a book called The Idiot's Guide to Being a Medieval English Party Animal, Falstaff would have written it.) Still, in Henry IV Part 2, Henry coldly banished his old chum, "on pain of death," from his presence (Henry IV Part 2, 5).
By the time we get to Henry V, Falstaff is seriously ill and his friends say the old knight is dying of a broken heart because King Henry has rejected him. At one point, Mistress Quickly declares, "The king has killed his heart" (2.1.86), and everyone pretty much agrees. Soon after, we're told flatly that Falstaff "is dead" (2.3.5). Apparently, he's succumbed to some kind of nasty venereal disease, which is sad but also fitting in light of Falstaff's penchant for brothels and taverns.
We know what you're thinking, Shmoopsters. If Falstaff doesn't ever appear on stage and is killed off by some kind of STD in Act 2, then why the heck are we talking about his character?
To answer your question, we turn to Falstaff's biggest fan, Shakespeare scholar Harold Bloom (who often refers to himself as "Bloomstaff"). According to Bloom, "The absence of Falstaff is the large presence in this drama, since Hal is thereby absent also" (Bloom's Shakespeare Through the Ages: Henry V). To put it another way, Falstaff's absence in this play is a reminder that Henry is no longer the rowdy teenager he used to be – "wild Prince Hal" is long gone and King Henry V is a serious and capable monarch who has said goodbye to his former bad-boy days.
Okay, fine. We get why King Henry can't be pals with Falstaff anymore, but why did Shakespeare have to go and kill the guy off in this play? (Why did he do it off-stage? This seems especially insulting, don't you think?) After all, in the Epilogue of Henry IV Part 2, Shakespeare promised us that he would send Falstaff off to the war in France. What gives? For some critics, the answer is simply a matter of casting. It's been argued that the actor (probably a guy named Will Kemp) who played the role in Henry IV Part 1 and Part 2 was unavailable. (Kemp left Shakespeare's theater company, The Lord Chamberlain's Men, in early 1599.)
Other critics say that Falstaff was just too much for this play. Harold Bloom asks, "If we shipped Falstaff from Shrewsbury to Agincourt and the fat knight went into battle there, carrying a bottle of sack [booze] instead of a pistol in his case or holster, would not the play break apart?" (Bloom's Shakespeare Through the Ages: Henry V). Okay, this makes sense to us. Falstaff has a tendency to inject plays with the spirit of rebellion and disorder, which isn't exactly what Henry V is all about. In other words, Falstaff's rowdy, larger-than-life character would have totally undermined Shakespeare's portrayal of King Henry V and would have demolished the play's patriotic tone by making a mockery of everything.