Arlan Northcrest was an ancestor of current Baron Elias Northcrest. It is not known if he was an ancestor before the reign of House Northcrest, or if he was born during their reign as Barons of the City. He is the subject of a painting acquired by Oxheart Perry.
If he was a Baron he would make an eleventh known Northcrest to have become Baron (but only ten Barons are ever countered among the dynasty, with Ulysses Northcrest being the first, and Elias being the tenth).
"Arlan Northcrest" is similar to "Harland Northcrest," such that the nameplate on the painting may have just had the H and the D rubbed off, and is intended to be the same individual.