I did some searching about and it looks like Ignis will not play like Nirvana, as she is not always present in the screen shots. I reckon she can be teleported in and will play similarly to Valkenhayn's Wolf Gauge.
Deus Ex Achievement Guide | xbox.com
Retail Completions: 38 | Arcade Completions: 15
Seriously 3.0: Total Onyx Medals - 24/65 | Level 86
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