Nothing stops a warlock from wielding a light pact weapon in one hand and a shadow blade in the other. With that combination, you could attack twice with Thirsting Blade and make a bonus action attack with the shadow blade. I'm still confused, new to light weapon fighting. How is there an attack with bonus action? Thirsting Blade gives 2 attacks with pact weapon only. Does the Shadow Blade always cost a bonus action? Thought it was just a bonus to cast, and then you use like normal weapon.
— Travis Dvoracek (@LedeshHevent) November 15, 2017
Because the shadow blade is a light weapon, you can use it with the rule on two-weapon fighting in the Player's Handbook (see p. 195). #DnD https://t.co/myYUEigtRF
— Jeremy Crawford (@JeremyECrawford) November 15, 2017
Cool as it sounds, doesn’t it only become a net gain of attacks on round 4? I wouldn't recommend casting shadow blade if your primary goal is to increase your number of attacks.
— Jeremy Crawford (@JeremyECrawford) November 15, 2017