As a Necromancer, Yu Chen was theoretically not proficient in close combat.
Of course, for a Necromancer who could summon an army with a mere wave of his hand, whether or not he was adept at close combat was actually quite irrelevant.
However, what Yu Chen lacked was the most important thing for a Necromancer: accumulation.
Powerful Undead Servants are a direct reflection of a Necromancer's strength and knowledge, but Yu Chen lacked the time and resources to create and research powerful Undead Servants.
The Combat Golem he had just summoned represented most of the combat force he had been able to produce through the Necromantic Space over the past year. As for the two Reaper Maidens, they had been summoned through the sacrifice of the torn-apart Combat Golem and were not his permanent Undead Servants; they would disappear once their summoning time was up.