Buffs of the same type will NOT stack, but there are some similar abilities that do work together. For example, the attack buff from Ares, Boldtusk, and Kiril do not stack - so whichever one you cast LAST takes priority. However, Wu Kong will stack with those attack buffs because he also reduces accuracy, whereas Brienne will not stack because her ability is just an attack buff though it changes as you get hit. Similarly, defense dubuffs such as Grimm, Gormek, Tiburtus, Isarnia, and Athena do not stack, even though Athena’s is slightly different again. Another notable exception is Alberich, who does stack with the mana regen from Lancelot and Khagan because their mechanics are slightly different.
This also works in reverse, where an attack buff will override an attack debuff, and vice versa. i.e. if you get hit with Skittleskull’s special and then cast Boldtusk’s special, you will cancel out the attack reduction and also gain Boldtusk’s attack increase in full. This is a very useful interaction to note for titans, where bear banners and turtle banners will reverse the effect of green and blue titans respectively.
You saying the color of the banner has an affect like hero color? If Scarlet on offense and red tiles hit Skittle, the atk is double. Is it additive with the red banner and Scarlet’s team shoots red tiles? And even more if versus green titan?
No, same debuffs and buffs don’t stack, color of buff is irrelevant.
To your 1st question. 2 li xiu can work. There is nothing to stack as her attack hits, takes.mana is done. If you had 2 fire, the opponent would lose 40% mana
DOT abilities don’t stack within the same type. Burn abilities like Marjana, Azlar, and Natalya will override one another. Same for poison abilities like Sartana and Oberon. However someone can be poisoned and burned at the same time.
Looks like a Derric on your defensive team, but when hit turns into the inquisitor and makes the hero who hit him sit in the comfy chair - reducing their attack and defense by 100% for the rest of the battle.
There is an easy way for you to find out yourself: Use an ability, then hold down on the hero and you can see all the effects currently placed on it. Then you’ll know if the ability stacks for future reference. I hope this helps.