She could be used either way, but her build should be tanky. Lots of HP%, Resistance, and defense. Her main tool is her Miasma and Thorns which deal constant damage no matter how high hp the opponent is. And it's useful to avoid the Block Busters. Use her shadow clone SMs to keep the opponent blocking and have time to build up miasma and thorn stacks. Evergreen Evil double is her best friend as they increase the duration of her buffs!
As an attacker, I should say I didn´t saw her in that mode, until some top player made a vid about how impresive she could be just standing there and winning. Totally a beast in attack.