Gu Mengmeng and Ian were so engaged in their conversation that they completely did not notice Gregory's envious gaze behind them.
He was extremely unsatisfied towards Ian's tone when speaking to Gu Mengmeng and this dissatisfaction surpassed the dissatisfaction he felt when Ian went against the Motou Mountains's vow.
Because it was his duty to kill Ian according to the vow but he also wanted to kill Ian because of his attitude towards Gu Mengmeng that made him growl internally.
And when he looked at the current situation, his anger subsided and all that's left was loneliness.
Ian and Gu Mengmeng were not partners and they had their own partners too. It seemed like they did not stay together for a long time but whenever they met, they did not feel the least distant from each other.