The phrase "although loyal" is correct and usable in written English.
It can be used to introduce a contrast or exception regarding someone's loyalty in a sentence.
Example: "Although loyal to the company, she decided to pursue a different career path."
Alternatives: "despite being loyal" or "even though loyal".
Although loyal to the team, he has a devil-may-care attitude, and Omi is a frequent target of his jokes.
Although loyal to the Church of England, he feared that his anti-trinitarian beliefs -- he thought that regarding Christ as God was a sin -- would destroy his career.
Although loyal to his party, Orme threatened to resign unless there was a free vote on direct elections and proportional representation for the European assembly.
Although loyal, I admit I'd long wearied of Fellowes's repetition come Downton's finale (not another story about one cook secretly helping another one make a stew!) and wished he'd farmed out some of the writing like most showrunning creators.
Although loyal to the ruling state, they were outside the customs zone and had their own laws.
But although normally loyal, Aldington expected his critical judgment to be taken seriously.
Although many loyal fans cannot openly admit it, Yankee Stadium is old, outdated and needs to be replaced soon.
His father was a Czech Communist diplomat, who was displayed in a show trial, and, although a loyal Communist, sent to a labor camp.
Although its loyal audience and uniqueness might help offset its lack of corporate clout, when it comes to negotiating rates with cable operators, the Weather Channel has avoided demanding high subscriber fees.
It was surrounded by towers of white roses for his county; although fiercely loyal to Leeds, he was almost as keen on Scarborough, which is determined to get up the first statue of him.
"Although a loyal professional at Portman Road from 1973 to 1987, the defender only made a total of 79 first-team appearances, nine of them coming in loan spells at Grimsby and Peterborough.
