— Kertz at the beginning of The Last Tiger
Kertz is a supporting character featured in the singleplayer of Battlefield V. He is the driver and mechanic of Tiger 237 commanded by Peter Müller. He is mentioned in the prologue My Country Calling, and takes a more prominent role in the singleplayer war story The Last Tiger.
He and Müller have a close friendship, having been together as far back as Tobruk in 1941. Although trusting in his competencies as a commander, having known him for so long he can see through Müller's artificial enthusiasm conjured from his patriotic adages. Unlike the rest of the crew he sees from the very beginning of the story that the war is lost. As such he has a strong dislike of the blindly zealous Schröder, however despite this cynicism, he cares for traumatised defeatist Hartmann and fights wholeheartedly to get the crew out alive. It is also clear he has some affection towards the tank, whom he and Müller refer to as "Stefan".
Calm and knowledgeable both in battle and when performing repairs, Kertz' bravery comes from years of experience and confidence in Müller, although he too eventually realises further fighting is fruitless after the crew is sacrificed to prolong the war. Kertz has a picture of a woman at his crew station, suggesting a wife or partner.
Although not seen, he is present alongside Müller during the Libyan section of the prologue in 1941. The pair survive many battles before Spring 1945, the setting of The Last Tiger. He appears relaxing on the roof of the tank watching swarms of Allied aircraft overhead while waiting for resupply and a replacement radio operator, neither of which they receive. Instead, Müller and Schröder arrive with new orders to advance over the bridge and attack the Twelfth Army Group's armored spearhead in the city. He criticises Müller for indulging and encouraging the fanatical Schröder, whom he compares to a lost dog. Kertz questions why the Germans do not just blow the bridge to keep the Americans at bay, but obeys Müller's orders.
Later on, the tank comes under rocket attack from Mosquitos, and Kertz takes the Tiger through a ruined building to hide. When the question is raised as to who will leave the tank to scout for a safe exit route, Schröder suggests Hartmann. Kertz protests, declaring him "in no fit state" for such a mission, and even volunteers in his place, but is considered essential to the crew by Müller who subsequently sends Hartmann. After he leaves and fails to return, Schröder asserts he has deserted, while Kertz continues to defend him. Suddenly, the crew is threatened with encirclement by an approaching US tank unit, and the Tiger flees the position without Hartmann aboard.
As night falls, the crew come across the hanged body of Hartmann who has been labeled as a traitor. Kertz stops the tank in front of him, forcing Müller to look up at the corpse. Schröder dismisses Hartmann as a traitor - Kertz asserts that "he was one of us" before driving on.
The crew arrives at the cathedral, the rally point for the "big defense" and find themselves alone there. As Müller searches on the radio for traffic, Kertz laughs in disbelief declaring that things have finally fallen apart. He asks Müller what they should do now but receives no reply. The tank is soon surrounded by American forces requesting their surrender, but Schröder opens fire on them. Holding the line against waves of enemy tanks, they are finally forced into retreat by artillery fire, and Kertz makes for the bridge. As they approach the crossing, an explosion rips through the structure, and the Tiger is sent skidding down an embankment as the road beneath them collapses. The vehicle throws a track, rendering it immobile, and Kertz is injured.
With the crew having been lied to fight on, presumably buying time for the demolitions to be prepared, this event serves as the last straw for Kertz' resolve. He dismounts and limps away from the wrecked tank. Müller intervenes, but his vague words of reassurance ring hollow for the both of them as Kertz becomes inconsolable over the things they had believed in and the things they had done in service of those beliefs. He declares that "it's over" before turning to leave. Immediately after, he is shot in the back by Schröder, who brands him a traitor. A devastated Müller leaps from the tank to cradle his dying friend while Schröder begs his commander to return to the tank. Amidst a gunbattle with arriving US troops, Müller discards his Iron Cross in the dirt next to Kertz' corpse.
- When first encountering the T34 Calliope in The Last Tiger, Kertz will remark "What the hell is that thing?", despite the crew having already fought the tank in Libya during My Country Calling.