
Fluellen provides the play's most sustained comic voice among the soldiery — a Welsh captain whose pedantic devotion to the 'ancient disciplines' of proper warfare is both a source of running humour and, at key moments, a genuine moral compass for how the campaign ought to be conducted.
Fluellen is a Welsh captain in Henry's army whose defining passion is for what he calls, in his distinctive accent, 'the disciplines of the war' — the classical and historical precedents of proper military conduct, which he cites at every opportunity with a scholarly enthusiasm that other officers find by turns endearing and exhausting. His comparison of Henry to Alexander the Great, garbled through his own pronunciation into 'Alexander the Pig,' is one of the play's most affectionately comic moments, precisely because the mangled comparison does not undercut Fluellen's genuine and touching sincerity.
His devotion to proper discipline is not merely theoretical. He reports, with evident personal regret, the execution of Bardolph for looting a French church — a man he liked, he admits, but whose crime the disciplines of war cannot excuse — and he polices the conduct of the army with the same rigor he applies to citing ancient precedent. When French raiders slaughter the boys guarding the English luggage, Fluellen is the one who draws the enraging comparison that helps push Henry toward ordering the prisoners' deaths, evidence of how seriously the play takes his notions of honourable and dishonourable war.
His comic revenge on Pistol, forcing the braggart to eat a raw leek at swordpoint after Pistol mocked the Welsh custom of wearing one on St David's Day, is Fluellen at his most memorably himself — proud of his nation, quick to avenge an insult to it, and entirely without malice once the debt of honour is settled. His warm loyalty to Henry, a fellow Welshman by birth, is genuine and mutual, and the king's private joke at Fluellen's and Williams's expense after the battle depends entirely on knowing how seriously, and how good-naturedly, Fluellen will take it.
Fluellen is motivated by an earnest, almost scholarly devotion to correct military conduct and to the honour of his own Welsh heritage — he wants the war fought properly, by the old rules, and takes any departure from those rules, by friend or enemy, as a personal affront.
Fluellen's talk runs long and circles back on itself, citing 'the Roman disciplines' and classical precedent with a scholar's enthusiasm that far outpaces his listeners' patience — but beneath the comic garrulousness is a genuinely honourable soldier, quick to report wrongdoing even in a man he liked, and quick to demand satisfaction when his nation's customs are mocked. His pride in being Welsh, and in Henry's own Welsh birth, is entirely unembarrassed and entirely sincere.