万人之敌

万 = 丆 + ㇆ : As mnemonic symbol I choose a neuron, since each neuron is said to connect to 10000 others.

万 = 丆 + ㇆ : Willy Walrus needs to dig up the floor in the anthill's bathroom, but he is tired of doing so manually with a plough. To make his life easier, he sets up a wind wheel for electricity, connects a neuron to the wind wheel and the plough to transmit the electricity and uses his new DIY electric plough to dig much faster.

人 = 丿 + ㇏ : Mnemonic symbol: Neanderthal Man (人). Robinson Crusoe (r-) is looking for snacks in the encampment's kitchen (-en2) when he suddenly spots Neanderthal Man (人). Neanderthal Man offers him a banana (丿), but Robinson Crusoe doesn't trust the present and pokes it with a finger (㇏).

之 = 丶 + Z : Mnemonic symbol: Sooo sleepy... "zZz" (the character looks like a "Z"). James II of England (zh) fell asleep in front of the space station (Ø1). He sleeps on a big petal leaf (丶), making loud "zZz" (之) sounds.

敌 = 攵 + 舌 : Dorothy Gale (di) is fighting her enemy (敌), the Wicked Witch of the West, by attacking her with a sledgehammer (攵) while threatening her with her tongue (舌) stuck out just inside the space station's entrance (Ø2).