This build was built to overcome the pantheon's downsides. Pantheon is a champion that performs poorly at the end of the game, not staying safe in battles, because he has no mobility and his normal build doesn't allow him to do long trades without being killed, especially good engages with W and his ultmate . This build allows you as a support, to abuse your W and your ultmate efficiently, aggressively and safely, giving your team a great advantage. At the beginning of the game you will have your character's high initial damage, ensuring constant lane pressure with your adc. Building Divine Sunderer as a first item is for you to make a smoother transition from damage to resistance. Initially the damage is of great importance so you can give your adc a significant advantage, and be able to create a fast snowball in the game in advantage of kills, farm and dragons. After the Divini Sunderer, a stamina build becomes the best option, because your goal now will be to safely and efficiently abuse your ultmate and W by engaging aggressively and staying in battles for a long time. Holding out for a long time in battle makes you a problem for everyone who wants to reach your adc.