Without Alfred Pennyworth, it’s highly unlikely that Bruce Wayne would have become the Batman we know and love. The public knows Alfred only as Bruce’s butler, but his service is more than just providing "Master Wayne" with tea and meals. He’s also arguably the Caped Crusader’s most trusted confidant, and in many stories, even raised him after his parents were gunned down. He’s been a key figure in Batman’s life for over 75 years. However, in terms of his official capacity in Batman v Superman: Dawn of Justice, Jeremy Irons’ Alfred isn’t Bruce’s butler, but rather his bodyguard
A new image of Bruce and Alfred together in the Batcave (via WhatCulture) has provided more details about their relationship in the DC Extended Universe. Alfred was originally hired to protect young Bruce, but after Thomas and Martha Wayne were murdered, Alfred was the only member of the Wayne Manor staff that Bruce kept around afterwards. Publicly, he’s seen as Bruce’s chief of security, but it was his SAS (Special Air Service) training that allowed him to train Bruce and assist with crimefighting. It’s also mentioned that it was Alfred’s decision to leave Wayne Manor since he couldn’t maintain it by himself. Now, when he’s not accompanying Bruce on business trips or to their underground hideout, he lives in a "comfortable trailer" on the Wayne Manor grounds.
Jeremy Irons has said before how his Alfred will feel different compared to previous interpretations, and we’ve definitely seen that in the previews. Described as a "grease monkey," he keeps the Batmobile and Batman’s other vehicles and gadgets in working order. We also saw him in the recent trailer controlling the Batplane and providing intel to Batman on hostiles while he was out in the field. So for this continuity, he’s definitely more "hands-on" in participating in Bruce’s vigilante life, which is why the chief of security title feels more fitting than mere butler.
As far as his military experience goes, this is the latest opportunity Batman media has taken to make Alfred more of a badass. Modern stories in the comics have mentioned Alfred’s SAS past (including Michael Caine’s iteration in the Dark Knight trilogy), but it was the Geoff Johns-penned graphic novel series "Batman: Earth One" that popularized him as a fighter, though in that universe he was a member of the Royal Marines. Since then, Fox’s Gotham and the animated series Beware the Batman have featured their Alfred beating up bad guys.
Beyond his combat experience and technical prowess, Alfred will also continue to provide alternate viewpoints to his employer’s crusade on injustice. Just like his previous incarnations, Irons’ Alfred has no problems giving Bruce blunt and direct comments ("Even you got too old to die young. Not for lack of trying"). So when Bruce decides to take action against Superman due to the threat he might pose against humanity, Alfred takes the opposite stance, telling him that he’s going down a dark path, and that to fight the Kryptonian is "suicide." Batman has always been stubborn, but sometimes he needs Alfred to set him straight or give him another opinion.
We’ll see how Alfred plays into Batman v Superman: Dawn of Justice when it hits theaters on March 25.