Complex sentence: While he can be merciless and unrelenting when getting a point across, he is also (at least superficially) understanding of others, willing to spare those he sees as potentially useful, and has been shown to be reasonable when people attempt to negotiate with him.
Split into simpler sentences: While he can be merciless and unrelenting when getting a point across, he is also (at least superficially) understanding of others and willing to spare those he sees as potentially useful. Yet, he has been shown to be reasonable when people attempt to negotiate with him.