Charles has made no secret of what's driving him: a shot at the Premier League, the level he narrowly missed out on when Southampton's play-off campaign ended in May.
That ambition now has Fulham willing to pay for it. Having already brought in Real Madrid pair Gonzalo Garcia and Cesar Palacios for a combined £46m, Alvaro Arbeloa identified the Northern Ireland international as the midfield reinforcement he still wanted, and Fulham have gone back in with an improved offer of £25m plus add-ons after Southampton knocked back their opening bid.
Southampton's asking price of £30m has proven a tougher barrier for other suitors. Leeds United spent weeks trying to get a deal over the line before abandoning talks last month, unable to meet what they considered an unreasonable figure.
Fulham appear more prepared to pay it, with Charles's willingness to push for the move giving them extra leverage in negotiations. The 22-year-old, a former Manchester City academy product who can operate across midfield or at full-back, scored the winner in Southampton's FA Cup upset of Arsenal last season and contributed six goals and two assists in 38 Championship appearances — form that has kept his stock up even as his club's promotion hopes collapsed.
Manchester City hold a sell-on percentage from his 2023 departure, meaning any fee agreed will be split further. Fulham's business with Charles is not their only outstanding piece of work: they remain in parallel talks over a deal for Real Madrid teenager Thiago Pitarch.
For Southampton, letting Charles go now carries its own logic. He has a single year left on his contract, and with the club already facing a difficult return to Championship life this season, banking a substantial fee rather than risking losing him for a smaller sum next summer looks the more sensible path.
Arbeloa, for his part, is building a Fulham squad around younger, hungrier profiles capable of adapting quickly to his methods, and Charles's combination of Premier League pedigree at academy level and genuine first-team hardening in the Championship fits that brief closely.
Whether Southampton's resolve holds at £30m or whether Fulham's £25m proves enough to get a deal over the line is likely to become clear within days rather than weeks.