This addon adds a undertale dialog box that you can use with chat commands. It was a rewrite of this addon here: https://steamcommunity.com/sharedfiles/filedetails ...

xp_uds_name: Change the displayed name. xp_uds_soul_color_r: Red value of the heart/soul. xp_uds_soul_color_g: Green value of the heart/soul. xp_uds_soul_color_b: Blue value of the heart/soul.