Len lacks confidence. He's very friendly, but often fails at keeping up conversations for multiple reasons. His speech is a bit broken, purely because he doesn't speak the common language very well yet, and he tends to turn the ends of sentences into mumbles. When he's comfortable, he's a very light-hearted and spirited guy, but it takes a lot for him to get to that point.
Above all, he values helping others and hates being alone.