Manticore only attacks when in second position. Having it in the middle of your deck means it was wasted. You picked the right cards but in the wrong combination (possibly)
Switch the Manticore to second spot so you would have benefitted from its attack and put your Dark Enchantress in last position. The Pixie has very low health so by swapping Manticore and Enchantress to new positions it adds extra attack and strengthens up your tail (keep furious chicken in the last slot as cannon fodder).
I love to read your posts, you obviously have developed a love for the game and enjoy writ3about it as much as I do. @splinterlands weekly contests are fun and cool to enter, let's see what they hit for us next Monday.