Let me explain, how you can collect runes by raiding normally.
I did 15 raids and got 20+ rewards in those raids. I have 30% luck ring and some luck pro bonus. However, this brings luck in Chamber of Fortune. Maybe, it is a luck for me or there it is a best ability to collect all runes in one battle.
Tips: Never destroy structures with your king. Never Ever! let your troops and spells take it over. Use slowdown effect of Toxic or Blizzard so that you can stop units and Mass Hysteria from attacking you.
Then, keep rotating your king. here and there. Keep rotating means, keep your king, revolving around some troops again and again, similar to what you do while equipping a heal aura ring and healing your troops. Dont just stand, keep moving. Rotate yourself.
In easy words, just put your finger on the screen, and tap the king and press it. Then, make a circle, and then, keep making circles going ahead the path. Let your troops to the raiding and you just run here and there.
This may seem to be a foolish idea at once. But this way you can ensure the maximum rewards, as your king have visited every part of the path, while raiding.
Sometimes, I even got three rewards in one raid, and mostly two. Only one or two raids our of so many… got empty.
Best of Luck! Keep raiding!