What UncleJJ said.
Also, you can try to level him up with animals escorting him with a scout to avoid spiders and such.
But instead of thinking of Lucian as a city cracker you can think of him as a very earlier harasser.
Depending on the difficulty level, instead of just trying to crack a city in any way, just make Lucian go very early with a group of beastmen and choke an opponent.
Pillage, attack their warriors on the field to level up, prevent them from expanding.
Meanwhile, you expand freely without worrying about barbarians - this is how you take advantage of the aggressive and barbarian traits.
Expand in the land that was supposed to be theirs - you don't need to defeat them right there and then.
Charadon has a much easier time doing this than most leaders. Usually you expand and prepare first and attack later.
Actually this leader kind of needs to do what I was saying or fall behind. But he's playable with some work.
This is more difficult to do on highest levels because you can easily face a strong counterattack.
If you start a war you have two options: you can take out opponents or cripple them.
If you can't take them out, take advantage of a well supported Lucian to do the later.
Do it early.